Charcot-Marie-Tooth (CMT) Disease

Charcot-Marie-Tooth (CMT) disease is named after the three physicians who first reported it in 1886. CMT is a group of genetic diseases that causes muscle weakness and wasting, or atrophy, in the feet, legs, hands, and forearms, as well as diminished sensation in the limbs. CMT disease affects the peripheral nerves-the nerves that travel to the muscles of the limbs and is therefore known as a peripheral neuropathy. Estimated to affect one in 2,500 individuals, it is the most common inherited neurological disorder.

The Tox 1401 students recently went through a 2010 paper where a CMT family was screened by sequencing the genome of a proband (an effected founding individual of a group). In this study the sequence from the proband was compared to reference genome sequence. This analysis which initially started with more than 3 million genetic differences between the proband and the reference genome group ultimately narrowed the genetic difference in this CMT family to the SH3TC2 gene.

If you would like to read more, I am asking the Tox 1401 students to head on over to the OMIM  site and give us some background on the SH3TC2 gene product and how mutations in this gene might effect neuronal function.

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76 thoughts on “Charcot-Marie-Tooth (CMT) Disease

  1. The SH3TC2 gene is apart of the ‘small gene family’. The SH3TC2 gene product encodes a protein that is expressed in Schwann cells of peripheral nerves. This gene encodes a protein with ‘two N-terminal Src homology 3 domains and 10 motifs”, and is also useful for the location of proteins in the cell membrane.This protein has been found in the ‘compnents of the endocytic pathway’ and in COS-7 cells’ plasma membrane. The SH3TC2 gene controls certain neuronal functions, and mutation in the gene may cause unfortunate effects. These effects include ‘autosomal dominant patchy axonal polyneuropahy, with definite median-nerve mononeuropathy at the wrist’, and increased chance of having carpal tunnel syndrome. Mutations in the SH3TC2 gene can also cause a stop condom to produce “premature truncations removing most of the C-terminal TPR domains’ that can result in a pattern like that of a wildtype protein.

  2. The SH3TC2 is a gene that is located on Chromosome 5 in human DNA. It is only expressed on human Schwann cells. These Schwann cells wrap the myelin sheath around nerves, and these cell are support neurons for the human Peripheral Nervous System (PNS). The human cDNA library was sequenced to produce clones of the full-length SH3TC2 gene, which was named KIAA1985. From this an ELISA (which we conducted in Tox 1401 L) was conducted from the KIAA1985 which found that this gene expressed itself mostly in the areas of the adult heart, testis, spinal cord, brain, fetal brain, and fetal liver. In contrast, little to no expression was found in the adult lungs, liver, kidneys, pancreas, spleen or ovaries. Through a technique named Northern Blotting (which was discussed in Tox 1401 lecture) the strongest expression of this gene was found in the brain and spinal cord.

    The SH3TC2 is known to interact with a guanosine triphosphate, (which have various functions , e.g., a source of energy for protein synthesis), named RAB11. Rab11’s specific role is to regulate the recycling of internalized membranes and receptors to return to the cell surface. If the interaction of SH3TC2 and RAB11 is hindered, the result is a decrease in myelin sheath formation. The Myelin sheath’s role (as previously noted) is to support nerve impulses. The Myelin sheath is located on the Axon, which is the part of the nerve cell through which the impulse travels. Any alteration of a part of the Myelin Sheath or the actual Axon results in a fatal condition known as Charcot-Marie-Tooth disease.

    Studies on the SH3TC2 gene of 11 different families showed that there is a possibility of 11 different mutations on the gene, a majority (7) of which occurred on exon 11. Such mutations could lead to fatal effects, which is true for any mutation on genes that effect and nerve impulses

    • I liked the way you started with describing the SH3TC2 as a gene that is located on chromosome 5 in human DNA. It’s very interesting that we both thought of starting with explaining the gene first then moving on to what it does. I even started by telling that this gene is expressed on Schwann cells. I totally agree that these mutations on the gene occurred on exon 11. The SH3TC2 mutation can surely lead to fatal effects in the peripheral nerves and result in Charcot Marie Tooth disease. You said that the interaction of SH3TC2 and RAB11 is hindered and the result is a decrease in myelin sheath formation. But I said that missense mutations of SH3TC2 could impair communication between the Schwann cell and the axon causing abnormal myelin formation. The alteration of a part of the myelin sheath or the actual axon can definitely lead to fatal condition such as CMT disease.

      • I completely agree with your description of Schwann cells. You had a smooth transition from your description of Schwann cells to copies of the SH3TC2 gene. I found your description of the different assays of the gene very interesting. Your mention of the interaction of RAB11 with SH3TC2 is a great explanation for abnormal myelin formation.

  3. Charcot-Marie-Tooth disease is a group of genetic disorders that affect the peripheral nerves. The peripheral nerves are essential for movement and sensation. According to the article “Whole-Genome-Sequencing in a patient with Charcot-Marie-Tooth Neuropathy”, which was published in the New England Journal of Medicine, it has been found through the process of whole-gene-sequencing that Charcot-Marie-Tooth neuropathy is caused by a mutant SH3TC2 gene . The SH3TC2 gene contains 18 exons and is located on chromosome 5. It is essential for peripheral nerve myelination.
    The expression on SH3TC2 is exclusive to Schwann cells of the peripheral nerves but the mutant gene in Charcot-Marie-tooth disease associates peripheral nerve myelination with endosomal recycling. It is localized in the perinuclear recycling compartment, which implies a role in myelination in areas of axogial interactions. The SH3TC2 gene mutations that cause Charcot-Marie-Tooth neuropathy disturb the production of the SH3TC2 protein. When the whole genome was sequenced in the proband, the cause of the Charcot-Marie-Tooth neuropathy was specifically found to be caused by compound heterozygous mutations in the SH3TC2 gene. The SH3TC2 protein includes SH3 and TPR motifs. Therefore, the gene effects neuronal function because its SH3 motifs mediate the assembly of protein complexes binding to proline-rich proteins, and TPR motifs are involved in the interactions of proteins with other proteins. Furthermore, since the SH3TC2 is known to have a function in endocytic processes, it only makes sense that a SH3TC2 mutant would cause disruption of the endocytic and membrane recycling pathways. Nonetheless, this ultimately causes muscle weakness and atrophy and decreased sensation to the limbs.

    • I liked the way you descried Charcot Marie Tooth (CMT) disease as a group of genetic disorders that affect the peripheral nerves. It was very simple but I also thought it was little general at the same time. You are so right the peripheral nerves are essential for movement and sensation. I think the SH3TC2 gene that is located on chromosome 5 is essential for peripheral nerve myelination. It’s so true that it is localized in the perinuclear recycling compartment, which implies a role in myelination in areas of axoglial interactions. I also mentioned that the expression on SH3TC2 is exclusive to Schwann cells of the peripheral nerves. But I think it does disturb the production of the SH3TC2 protein when there is a mutation. I agree with you that the SH3TC2 gene mutation can cause disruption of the endocytic and membrane recycling pathways and as a result CMT disease will occur.

    • I like your post because it is understandable. And you point out the SH3TC2 protein includes SH3 and TPR motifs which I did not menttion in my post.

    • Your explanation of the disease is detailed and clear. It is straight to the point and provides examples for the illness. You point out the specifics on where the disease takes place and what it does to the body.

    • I like how you were very specific about the gene. You explained it in a way that was easy to follow. I didn’t have any issues understanding where you were coming. You also made a lot of connections based on the knowledge you found out and learned.

  4. Charcot-Marie-Tooth (CMT) Disease is a group of diseases that causes muscles to atrophy. Charcot, Marie, and Tooth are scientist who collaborated together and are credited for discovering these diseases. These scientists discovered that this disease was a genetic mutation and thus a neurological disease. Recently, a different group of scientist sequenced the genome of a family with CMT. The genetic mutation was found as a single-nucleotide polymorphism on the SH3TC2 gene. The SH3TC2 gene encodes a protein expressed in Schwann cells of the Peripheral Nervous System (PNS). The PNS includes all parts of the body outside the brain and spinal cord. Schwann cells produce myelin sheath in the PNS. Myelin sheath are cells that wrap tightly around the axon of a neuronal cell insulating it and preventing the leakage of ions in order to conduct a fast action potential over long distances throughout the body. This mutation affects the Schwann cells which ultimately effects the production of myelin sheaths and slows the propagation of an action potential along a nerve. The action potential lacks the assistance of the myelin sheath allowing it to travel farther distances. Less action potential is able to reach the peripheral areas of the body such as the fingers and toes. This explains why individuals with CMT first loose nerve activity in their feet. There are two types of CMT disease: type 1 is a demyelinating form affecting the glial-derived myelin and type 2 is the axonal form affecting the nerve axon. This mutation ultimately affects neuronal function by damaging the axons which are the highways to and from the Central Nervous System.

    • I thought your post was great, it was understandable and informative. I loved how you explained how myelin aids in the communication between neuron. It clearly explains why people loose sensation and movement of their extremities first.

    • I liked the way you described what CMT is and described what the Peripheral Nervous system is because not a lot of people may know what it really is. You really broke things down and made it simple.

  5. The SH3TC2 gene mutation is present in genomic DNA in exon 11, which is located on chromosome 5. It encodes a protein expressed in Schwann cells of peripheral nerves. This gene mutation is localized to the plasma membrane and to the perinuclear endocytic recycling compartment. This suggests that it affects function in myelination or in regions of axoglial interactions. The SH3TC2 gene interacts with other proteins and assists in assembling proteins into a group or complex. It contains both SH3 and TPR motifs. SH3 motifs mediate the assembly of protein complexes binding to proline rich proteins, and TPR motifs are involved in protein interactions. The gene product has been proposed to be an adapter or docking molecule. The SH3TC2 gene is present in several components of the endocytic pathway. In endocytic processes, the SH3TC2 mutations result in disruption of the endocytic and membrane recycling pathways. Mutations in SH3TC2 gene result in autosomal recessive Charcot Marie Tooth (CMT) disease. This a childhood onset neurodegenerative disease characterized by demyelination of motor and sensory neurons.

    CMT disease has identified at least 19 SH3TC2 gene mutations that cause a form of CMT disease known as type 4C or CMT4C. This disease is a group of progressive disorders that affect the peripheral nerves. Peripheral nerves connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, heat, and sound. Most of the SH3TC2 gene mutations that cause CMT disease disrupt production of the SH3TC2 protein resulting in an abnormally short or unstable version of this protein. Some mutations change one of the building blocks, amino acids, used to make the SH3TC2 protein, which alters the protein’s structure. The endocytic and membrane trafficking pathway may be involved in the pathogenesis of CMT4C disease. These missense mutations of SH3TC2 could impair communication between the Schwann cell and the axon causing abnormal myelin formation. This autosomal recessive CMT4C is caused by heterozygous mutations in the SH3TC2 gene: R954X and Y169H. The Y169H missense variant segregates with an axonal neuropathy, whereas the nonsense R954X mutation is associated with subclinical evidence of the carpal tunnel syndrome.

    • Very clear and easy to understand description of the gene product and the effects of it’s mutation. With the time I’ve spent studying various kinds of conditions and disorders that effect the body and human health, I’m surprised that I’ve never come across this particular gene, especially considering it’s role in controlling such an important physiological feature. One thing that you mentioned that I was actually interested in finding out was the fact that this is a heterozygous condition, I thought that individuals expressing this condition would be caused by a homozygous mutation. Overall, your post was well organized and clear and you did a great job at successfully fulfilling the assigned task.

  6. SH3TC2 is a gene that encodes a protein expressed in Schwann cells of the peripheral nerves. The official name of this gene is “SH3 domain and tetratricopeptide repeats 2” but its official symbol is SH3TC2. The SH3TC2 gene contains about 18 exons. The molecular Location of SH3TC2 is on chromosome 5. The gene’s base pairs are 148,361,712 to 148,442,736. It is localize to the plasma membrane and perinuclear endocytic recycling compartment. This localization suggests that the gene has a possible function in myelination and/or in regions of axoglial interactions. The gene provides instructions for making a protein whose function is unknown. The SH3TC2 protein probably interacts with other proteins and may assist in assembling proteins into a group based on its structure. SH3TC2 undergoes mutations which lead to the development of disease known as CMT4C or Charcot-Marie-Tooth disease. This disease is a group of progressive disorders that affect the peripheral nerves. Peripheral nerves are known to connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, heat, and sound. Symptoms of the disease include weakness of the foot and lower leg muscles, which may result in foot drop and frequent tripping or falls. Foot deformities, such as high arches are also characteristic due to the weakness of the small muscles in the feet. Most of the SH3TC2 gene mutations which cause CMT4C disease is known to disrupt the production of the SH3TC2 protein. This results in an abnormally short or unstable version of the protein. Some mutations can change one of the amino acids used to make the SH3TC2 protein that alters the protein’s structure. It is unclear how SH3TC2 gene mutations cause signs and symptoms of type 4C Charcot-Marie-Tooth disease. Researchers have said to identify at least 19 SH3TC2 gene mutations that cause a form of Charcot-Marie-Tooth disease known as type 4C. Heterozygous and/or homozygous mutations in the SH3TC2 gene in patients with CMT4C also have been identified.

    • Marvin, I was interested in knowing if you ever heard of this condition prior to the assignment? I ask this because, according to the national institute of neurological disorders and stroke approximately 1 in 2,500 Americans are diagnosed with the condition. Even more startling to me is the relative early onset of the condition. I would have thought that such a condition would more likely effect older individuals, however, considering that this is an inherited condition, it appears the condition arises as a result of genetic predisposition and not old age!

    • I was interested in knowing if you ever heard of this condition prior to the assignment? I ask this because, according to the national institute of neurological disorders and stroke approximately 1 in 2,500 Americans are diagnosed with the condition. Even more startling to me is the relative early onset of the condition. I would have thought that such a condition would more likely effect older individuals, however, considering that this is an inherited condition, it appears the condition arises as a result of genetic predisposition and not old age!

  7. Charcot-Marie-Tooth disease is a group of progressive disorders that affect the peripheral nerves and result in problems with movement and sensation. Charcot-Marie-Tooth (CMT) disease – caused by mutations in the SH3TC2 gene. Mutations of SH3TC2 could impair communication between the Schwann cell and the axon causing an abnormal myelin formation. The SH3TC2 gene is located on the long (q) arm of chromosome 5 at position 32. Researchers have identified at least 19 SH3TC2 gene mutations that cause a form of Charcot-Marie-Tooth disease known as type 4C. Charcot-Marie-Tooth disease is a group of progressive disorders that affect the peripheral nerves. Peripheral nerves connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, heat, and sound. Most of the SH3TC2 gene mutations that cause Charcot-Marie-Tooth disease disrupt production of the SH3TC2 protein, resulting in an abnormally short or unstable version of this protein. Some mutations change one of the building blocks (amino acids) used to make the SH3TC2 protein, which alters the protein’s structure. Charcot-Marie-Tooth type 4C (CMT4C) is less severe than other autosomal recessive (AR) CMT. Spine deformities are clearly a hallmark of CMT4C. In the presence of scoliosis, a neurologic examination is recommended. Giant axons on biopsies are also suggestive of CMT4C.

  8. SH3TC2 is a gene that was mapped by the International Radiation Hybrid Mapping Consortium to chromosome 5. The gene is known encoding a protein expressed in Schwann Cells of the peripheral nerves, and is localized to the plasma membrane and to the perinuclear endocytic recycling compartment (19805030). It is suggested that it is possible for SH3TC2’s function be related towards mylelination and regions of axoglial interaction. A according to 19744956’s research, a mutation on SH3TC2 is capable of impairing communication between the Schwann Cell and the axon causing abnormal myelin formation. The mutation also is responsible for cauing the disease known as Charcot-Marie-Tooth disease.
    Charcot-Marie-Tooth disease is a neurological disorder that is also known as a hereditary motor and sensory neuropathy (Charcot-Marie-Tooth Disease Fact Sheet). The disease effects the motor and sensory nerves, and a common characteristic amongst those that have the disease is the fact that they will have weak foot/leg muscles. The symptoms of Charcot-Marie-Tooth disease are capable of developing between adolescence or early adulthood (some develop mid-adulthood). Fortunately, the disease is not considered a fatal disease, and most of the people containing the disease are capable of living a normal lifespan. CMT is caused by inherited gene mutations that affect the normal function of the peripheral nerves. These nerves slowly degenerate and lose their ability to communicate with their distant targets.

    Sources:
    -SH3 DOMAIN AND TETRATRICOPEPTIDE REPEAT DOMAIN 2; SH3TC2
    http://www.ncbi.nlm.nih.gov/omim/608206
    PMID: 608206

    -SH3TC2/KIAA1985 protein is required for proper myelination and the integrity of the node of Ranvier in the peripheral nervous system.
    http://www.ncbi.nlm.nih.gov/pubmed/19805030
    PMID: 19805030

    -Missense mutations in the SH3TC2 protein causing Charcot-Marie-Tooth disease type 4C affect its localization in the plasma membrane and endocytic pathway.
    http://www.ncbi.nlm.nih.gov/pubmed/19744956
    PMID: 19744956

    -Charcot-Marie-Tooth Disease Fact Sheet
    http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001741/

    • Wow, you used a lot of great sources. I agree with you on SH3TC2′s function be related towards mylelination and regions of axoglial interaction. You also mentioned that it was lethal and I think that is sad because it can start as early as mid-childhood.

      • I agree with you and Jason on the fact that it’s very unfortunate that it happens to such young children. That is the time where children and growing and learning what they are capable of physically and mentally. It’s terrible that physically they won’t be able to perform to their full capacity as they would mentally.

    • You listed a number of reliable sources for this disease. You used the phrase “according to” to state where the facts originated from. I agree with you on how the disease is not considered a fatal disease and most patients having this illness can have normal lifespan.

    • I liked the way you cited so many sources…no wonder this blog post is so imformative! This gave a lot of clear information and made a lot of sense because of the way you put things together and the simple words that you chose. You also defined a lot of things that should have been known!

  9. Charcot-Marie-Tooth disease is a name for a number of genetically inherited diseases that affects the peripheral nervous system. The peripheral nervous consists of all nerves that don’t include the brain and spinal cord. Its notable symptoms are loss of muscle tissue and touch sensation, predominantly in the feet and legs but also in the hands and arms in the advanced stages of disease. Recent studies have shown that the origin of cause is a mutation in the gene SH3TC2. This mutation is an example of a single nucleotide polymorphism which is a single nucleotide change in the sequence of a gene compared to its normal one. This single nucleotide change makes the incorrect expression of a protein in a glial cell in the peripheral nervous system known as Schwann cells which is responsible for myelination of axons. The main purpose of the myelin sheath is to increase the transfer rate of the nerve impulses or action potentials from neuron to the next. If action potentials fail to transfer, then there is a loss of responses to a stimulus or other important functions or changes in the body.

  10. Charcot-Marie-Tooth Disease (CMT) is a progressive neurological disorder that eventually causes damage towards the peripheral nerves. The damage affects their normal functions like carrying signals from the brain and spinal cord to various muscles in the body. The Charcot-Marie-Tooth disease results from mutations of the SH3TC2 gene. According to the US National Library of Medicine Genetics Home Reference page, “Most of the SH3TC2 gene mutations that cause CMT disease disrupt production of the SH3TC2 protein, resulting in an abnormally short or unstable version of this protein.” The SH3TC2 gene encodes a protein expressed in Schwann cells, so mutation of this gene could affect the normal myelin production interrupting the conduction of nervous impulses along the axon.

    • Very good. I felt the same way. Most of us know what myelin is and where it is located on the neuron, but you would have had an even clearer explanation if you introduced the nuerological disorder by introducing the anatomy of anueron.

  11. The SH3TC2, “SH3 domain and tetratricopeptide repeats 2”, is active in Schwann cells of peripheral nervous system providing instructions to make proteins which is function in myelination and in regions of axoglial interactions. The SH3TC2 gene is located in chromosome 5 from base pair 148,361,712 to base pair 148,442,736. The peripheral nerve that surrounds outside the brain and spinal cord is in charge of multiple functions and the main function of connecting the central nervous system to the limbs and organs. The Schwann cells and other types of supporting nerve cells are together to supply myelin sheath for supporting peripheral neurons in peripheral nervous system. Since the peripheral nervous system is consisted of motor and sensory nerve fibers, the effects of Charcot-Marie-Tooth (CMT) Disease are resulting in muscle weakness and sensory numbness. The SH3TC2 gene is known to target to the intracellular recycling endosome by associating with the small guanosine triphosphatase Rab11 known to regulate the recycling of internalized membranes and receptors back to the cell surface. The mutations of SH3TC2 cause neuropathy to disrupt the SH3TC2 and Rab11 interaction which leads to impair myelin formation. This damage of myelination ultimately weakens the muscles and decreases sensation of the limbs.

  12. Charcot Marie Tooth syndrome is a common, inherited neurological disorder affecting nearly 1 in 2,500 Americans. A disorder that causes muscle weakness and atrophy, a major factor contributing to CMT is SH3TC2 mutation. The gene SH3TC2 is a gene that is responsible for the coding of a protein expressed in the Schwann cells of the peripheral nervous system. Schwann cells are important cells that function as the glia (homeostatic cells) of the peripheral nervous system. Schwann cells form the conductive insulation of the neuron known as the myelin sheath. Myelin serves an important physiological function as it functions to increase the speed at which electrical impulses are propagated and. Mutations of SH3TC2 thus can result in demyelination or hypomyelination. Both are significant as deficiencies in the myelin sheath can result in difficulties in the conduction of nerve signals and impulses. This impairment oftentimes leads to difficulties in sensation, motor control and cognitive abilities. Located in the plasma membrane and near the perinuclear endocytic recycling compartment, the gene has been determined to contain a total of 18 exons and has been mapped by the international radiation hybrid mapping consortium to chromosome 5. In 2009, researchers discovered that mice lacking the SH3TC2 gene displayed progressive peripheral neuropathy resulting from reduced nerve conduction velocity from the motor and sensory nerves, in addition to significant hypomyelination.

  13. Marvin, I was interested in knowing if you ever heard of this condition prior to the assignment? I ask this because, according to the national institute of neurological disorders and stroke approximately 1 in 2,500 Americans are diagnosed with the condition. Even more startling to me is the relative early onset of the condition. I would have thought that such a condition would more likely effect older individuals, however, considering that this is an inherited condition, it appears the condition arises as a result of genetic predisposition and not old age.

  14. The Charcot-Marie-Tooth disease is a genetic disorder that affects the peripheral nervous system needed for sensation and movement of the body. The disease is linked to the gene SH3TC2 found on chromosome 5 and encodes a protein needed for the myelination of the peripheral neurons. Myelination is the process of insulating the neuronal axons and helps increase the speed of information to and from the nervous system. Without the myelin insulators, information to and from these neurons would be much slower. Eventually, no information will be able to move fast enough from the nerves to reach the brain or vice versa. This effects movement (you may not be able to move your limbs), sensation (you may not be able to feel anything) etc.
    The SH3TC2 which is located on chromosome 5, undergoes a mutation causing changes in the sequence. Scientists have discovered 19 mutations on the gene which effect the mRNA sequence that makes the needed protein. It will either produce no protein or an ineffective protein. The mutation is a complex heterogeneous pattern which enables the genome to have different phenotypes of the disease. This means the disease may have different levels of expression from genome to genome. One example is if a mutation happens to be in more than one gene related to the CMT disease, there is a more severe phenotype of the disease. But in the end, it means a degeneration of the peripheral nervous system leading to loss of sensation and movement.

    • Sadia,

      I find your research on this topic to be extremely informative. You used great detail in describing the effects of the mutation of the gene such as “The mutation is a complex heterogeneous pattern which enables the genome to have different phenotypes of the disease.” Its phenomenal how one gene can cause such great effects on the human body especially to children? I was wondering if they use these observations such as deformities to the human’s phenotype to diagnose a patient? Also, I like your use of insightful evidence where the scientists were able to discover 19 mutations on the gene. It’s amazing how advanced our technology got over the years. It would have been great if you mentioned what part of the human body actually get affected when there is loss of sensation and movement. Overall. Great work!

  15. In the human genome, the SH3TC2 gene allows a protein in Schwann cells to be transcribed. It is suggested that the function of this specific protein is to myelinate areas of the nerve. A mutation in this gene will effect the specific protein needed to produce proper myelination in the peripheral nerve cells. Myelinated nerve cells allow a signal to travel along the axon and without the myelin sheath, degeneration amongst nerve cells will result.
    For the most part, degeneration will take place in the motor nerve cells which weakens muscle and produces atrophy in the extremities. In some cases, degeneration in sensory nerves will reduce a person’s ability to sense heat, cold and pain.
    The mutations in the SH3TC2 gene are usually inherited which cause Charcot-Marie-Tooth disease. This condition is considered to be autosomal dominant, where only one faulty copy of the gene is needed to express the trait. Examination of a family’s medical history is one way to determine if an individual can inherit the disease. Medical professionals will also examine an individuals neurons for evidence of degeneration of the myelin sheath (Schwann cells).

    • Melissa,

      I find your explanation and further interpretation of this gene to be very informative. Not only did you state the exact function that this gene possesses but you went into further description of how the mutation of this gene affects the body. For example, when you mentioned that the mutation of this gene affects proper myelination and then you went into further detail of the importance behind myelinated nerve cells. A lot of individuals when reading scientific articles aren’t positive as to what exactly the method of action is behind each functional group and it is important that they have a clear understanding before beginning their research. Overall, excellent work!

  16. The SH3TC2 gene, also known as SH3 Domain and Tetra Tricopeptide Repeat Domain 2 or KIAA1985, is responsible for giving out instructions throughout the nervous system so different proteins can be made. Located in chromosome 5, SH3TC2 also assists with encoding proteins in the Schwann cells in the peripheral nerves. After cloning the SH3TC2 gene, it was found that it contains 18 exons, and exon 7 is capable of creating mutations. Changes in this gene can cause people to suffer from Charcot-Marie-Tooth disease, an illness that negatively impacts peripheral cells and cause muscle weakness throughout various parts of the body. Mutations from SH3TC2 can develop through exonization, when new exons are being produced, or stop codons, which can lead to missense mutations. These changes can cause impairments within the cells. Abnormal cells will start to function improperly, especially the myelin sheath. The myelin sheath is part of the axon of a neuron, and is essential in sending signals through the nervous system. If damaged, a person’s neuronal system will be affected greatly.
    For scientists to detect SH3TC2, various methods have been used, including PCR, ELISA, and Northern Blot Analysis. Each method is used differently and identifies this gene in various parts of the body. PCR, polymerase chain reaction, amplifies a specific part of a DNA from cloning and from this technique detected the gene in the brain, spinal cord, testis, and heart. Northern Blot Analysis uses gel electrophoresis can identify the presence of a transcript. If a SH3TC2 gene is present, it will be noticed based on its transcript in the DNA. ELISA, on the other hand can spot the different proteins available. Recognizing a specific gene or protein in a person’s DNA can help scientists decide what disease or mutation was created and how it affects the body. In this case, mutations in the SH3TC2 gene are a problem to the nervous system because it destroys the proper signals that are to be sent by blocking specific pathways.
    Sources:
    http://www.ncbi.nlm.nih.gov/omim/608206
    http://ghr.nlm.nih.gov/gene/SH3TC2

    • your comment was very informative. You clearly looked up a lot of information and your response on the topic informs us a lot about the gene and the mutations.

    • wow! Your post is really informative. You give lots of information about the gene and mutations. Good work.

  17. The nervous system involves a specialized network that enables the body to send and receive signals controlling both the body and the mind. Within this organ system, two main functions are responsible in the overall utility, central and peripheral nervous system. In this situation we will be focused on the peripheral nervous system that involves a gene known as SH3TC2. It’s a specialized gene that stays active within the peripheral nerves and is expressed in Schwann cells “that wrap the myelin sheath around nerves.” Its function is essential in providing the guidance in making a protein that has an indefinite purpose but after careful observation of the genes structure, it was almost certain that the protein is involved in a network of other proteins by interacting with them as well as helping them congregate into a formation of either a group or a complex. SH3TC2 “localizes to the plasma membrane and to the perinuclear endocytic recycling compartment” where it holds a part in myelination or in axon-glial cell interactions. Problems arise when a mutation in this gene occurs which further causes damages to the motor and sensory neurons due to demyelination. This result in autosomal recessive Charcot-Marie-Tooth disease type 4C that is portrayed in early-onset distortion of the spine. This is mainly witnessed and observed amongst children who are affected between the age group of two and ten years of age and that exhibit scoliosis or kyphoscoliosis. SH3TC2 is said to be the only gene associated with this mutation so several tests are done in order to conduct a sufficient diagnoses. Tests involve “motor nerve conduction velocity testing, and molecular genetic testing.” In the earlier or later stages of childhood, affected individuals witness progressive neuropathy and abnormalities in the foot is commonly developed.

  18. Charcot-Marie-Tooth (CMT) disease is a rare neurodegenerative set of conditions that has crippling affects. It is one of the most commonly inherited nerve-related disorders. The disease acts by gradually degrading the nerves in the feet, legs, arms and hands, usually starting during adolescence. This gradual degradation is due to the damage that occurs in the myelin sheath which acts as neuronal insulation which speeds up nerve conduction. Damage to the myelin sheath results in peripheral neuropathy much like occurs in CMT. One of the genes that encodes protein in Schwann cells is SH3TC2. Research shows that a mutation in this gene can lead to demyelination and thus onset of CMT. There is no known cure for CMT and some physical therapy ay only ease complications.

    http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001741/
    http://www.ncbi.nlm.nih.gov/omim/608206

    • This post was very informative and well researched. You really explained the topic clearly without being too wordy-a habit most science writers develop. Good job !

  19. Sources:

    http://www.ncbi.nlm.nih.gov/books/NBK1340/
    PMID: 20301514

    SH3TC2, a protein mutant in Charcot-Marie-Tooth neuropathy, links peripheral nerve myelination to endosomal recycling.
    PMID: 20826437

    N Engl J Med. 2010 Apr 1;362(13):1181-91. Epub 2010 Mar 10.
    Whole-genome sequencing in a patient with Charcot-Marie-Tooth neuropathy.
    PMID: 20220177

  20. The SH3TC2 gene is the gene that has been found that if mutated it may cause CMT disease which causes muscle weakness and atrophy. This gene has been found to be located on chromosome number 5 by The International Radiation Hybrid Mapping Consortium. The SH3TC2 gene encodes a protein that is expressed in the Schwann cells. Schwann cells are important as they help in regeneration of nerve cells as well as helping conduction of nerve impulses. In a certain type of CMT disease scientists have found 10 or 11 different mutations in the people that have the disease. The mutated gene produces a different type of protein which doesn’t allow the impulses in muscles to be received, without the impulses the muscles aren’t used and they die away.

    • I felt like your response was very fact given and to the point. I particularly lie it because it gives you all the necessary information to understand what the gene does without overwhelming you with the extra information one may not be familiar with.

  21. In a study by Lupski et al., they sequenced DNA using SOLiD (sequencing by Oligonucleotide Ligation and Detection).They “identify the cause of his disease as a compound heterozygous mutations in the SH3TC2 gene”. They also stated that “The mouse orthologue of SH3TC2 is specifically expressed in Schwann cells, and the SH3TC2 protein localizes to the plasma membrane and to the perinuclear endocytic recycling compartment, which is consistent with a role in myelination or in axon-glia interactions” (Lupski et al., 2010).

    The SH3TC2 gene encodes a protein expressed in Schwann cells of the peripheral nerves (Arnaud et al., 2009). Schwann cells supply the myelin for the peripheral nerves. They wrap themselves around the nerve axon. A single Schwann cell makes up a single segment of an axon’s myelin sheath. The myelin sheath increases the speed of the signal spreading along the myelined axon. A nerve cell communicates with other cells by sending electrical signals alone the axon. Without an intact axon and myelin sheath, peripheral nerve cells are unable to activate the muscle or relay sensory information from the limbs back to the brain.

    Charcot-Marie-Tooth neuropathy is caused by a mutation in the genes that produce proteins involved in the structure and function of either the peripheral never axon or the myelin sheath. The mutations decrease the affects of the peripheral nerves and eventually the nerves degenerate and lose the ability to communicate with their targets. The degeneration of motor nerves results in muscle weakness and eventually muscle loss.

  22. The Charot-Marie-Tooth disease, one of the most common inherited neurological disease, occurs to those who have a mutation in the SH3TC2 protein. It is also known as HSMN, hereditary motor and sensory neuropathy, or peronal muscular atrophy. This is a demyelining inherited neuropathy that is characterized by early on-set and scoliosis. Onset can be found in patients ages ranging from 2 to 10, but symptoms often show during adolescence or early adulthood. The progression of the symptons is gradual and may not present itself until mid-adulthood. Scoliosis can be found in almost all patients. Studies have shown that despite the deformities, the patients are able to walk without requiring help. This disease causes the motor and nervous systems to create abnormal proteins that affect the normal function of the peripheral nerves. This disease will first affect the feet and lower limbs, causing muscular weakness and eventually loss in muscle bulk. It may later occur in the hands, which will affect the patient’s motor skills. There is currently no cure, but physical therapy is advised.

    • Good response, straight forward and informative. Someone who did not know about this disease could learn about it through this piece.

  23. Charcot Marie Tooth disease is a neurological disorder that affects the sensory organs in the limbs of our bodies and is caused by the mutation in the SH3TC2 gene. This gene can be found on chromosome 5 on the long arm. Charcot Marie Tooth disease is can be broken down into two types. The first type affects the axonal form of our limbs while type 2 affects the nerve axon. This could make walking, breathing and speaking a difficult task. The severity of this disease depends on the family history of those who have had the disease and can vary significantly between individuals. Charcot Marie Tooth disease gradually causes distal muscle weakness, wasting and is common in patients with arched or flat feet. This disease can be passed on in an autosomal dominant, recessive and x-linked manner. Alteration or mutation in the PMP22, 11 MPZ, PRX, GDAP1, and EGR2 genes can result in this disease.

    • I enjoyed your detailed description of the symptoms of the disease and stated the different ways that the disease could be transmitted through a family or generation.

  24. The SH3TC2 gene, in humans, encodes a protein that is expressed in nerve cells in your peripheral nervous system and when mutations occur on that gene in an individual they form a disease known as Charcot-Marie-Tooth disease (CMT). The peripheral nervous system is composed of all the nerves that are not part you your brain or spinal chord. Peripheral nerves are those that are in your finger tips, toes, muscles, etc. Mutations on this gene cause CMT which is a hereditary disease that causes lose of muscle function and ability. CMT effects the nerve cells that muscles respond to for movement. When you move your arm up what happens is you brain sends a signal down a trail of nerves that eventually ends with a peripheral nerve right by your bicep or tricep that signals the muscle to contract and, therefore, move your arm up. CMT causes that last peripheral nerve near your muscle to get damaged, which causes you to loose your ability to move.
    The onset of CMT begins at birth, usually working from the outside limbs, in.
    In some people this disorder effects the myelin seath cells around the nerve cells, while in other people the disease causes the axon of the nerve cell to deteriorate. This disorder is very common; it is one of the most common nerve related diseases. There are different types of this disease which depend on which portion of the DNA sequence within the gene gets mutated. Depending on the mutated sequence, CMT can be autosomal dominant, autosomal recessive, or X-linked.

  25. Sources for post:

    “SH3TC2”. Wikipedia. Web. 5 Apr. 2011

    Q8TF17 (S3TC2_HUMAN). UniportKB. Web. 5 Apr. 2011

    Charcot-Marie-Tooth disease. PubMed Health. Web. 5 Apr. 2011

  26. Charcot-Marie-Tooth (CMT) neuropathy is an inherited peripheral disease that is caused by the mutations that affects the axon and the myelin sheath. Through neuropathological studies and electrophysiological studies, we can differentiate the two different forms of CMT: (1) a demyelination form and (2) an axonal form.
    In Baylor College of Medicine, Houston; Atlantic Neuroscience Institute, Summit, NJ; Mount Sinai School Medicine, NY; Life Technologies , Carlsbad, NY there was a study on a family with a recessive form of CMT Neuropathy through genome sequencing, identifying and genotyping the variants in the affect individual ones.
    After analysis, scientists discovered there were mutations ii the SH3TC2 protein (SH3 domain and tetratricopeptide repeats2). One mutation is in R954X allele correspond to the G→A mutation in exon 11 of SH3TC2 that results in elimination of TaqI restriction site, it is called the nonsense mutatoin. Another mutation Y169H is the missense mutation (A→G mutation) that corresponds to the amino acid mutation Tyr169His. From genome sequencing, it appeared that if the member only has one of those two mutations, he/she did not have CMT neuropathy. But for members who had CMT neuropathy, they carried both mutant alleles. The R954X mutation is associated with carpal tunnel syndrome and the Y169h mutation is associated with axonal neuropathy.

    • I liked how you included information about the specific elimination site that creates the SH3TC2 gene.

  27. The peripheral nervous system is made up of nerves that lie outside of the brain and spinal cord, with its main function being to connect the central nervous system to all of the different parts of the body. Schwann cells are non-neuronal cells that are vital to the peripheral nervous system, forming an insulated layer of myelin that is used to protect neurons. Myelination is of utmost importance because damage of the nerves can cause serious complications or disorders. It turns out that the gene that encodes a protein expressed in Schwann cells, the SH3TC2 gene, may be responsible for some of these disorders when they undergo specific mutations. This gene is located in the genomic DNA on chromosome 5. According to OMIM, missense mutations, such as R529Q and E657K, “in or around the region of the first TPR domain were absent from early endosomes, reduced in plasma membrane and late endosomes, and were variably present in clathrin-coated vesicles.” This specific mutation on the SH3TC2 gene was suggested to damage the interaction with the Schwann cell and the central nervous system, causing abnormal quantities of myelin to be formed.
    However, there were mutations found that produced different results. The mutations R954X and R1109X created stop codons that were introduced into the gene sequence that caused early truncation to occur, eliminating the C-terminal of the tetratricopeptide repeat (TPR). This allowed for the expression pattern that was seen in the wild type protein that the SH3TC2 gene makes. Nevertheless this type of mutation has been implicated with Charcot-Marie-Tooth Neuropathy. Patients who are only homozygous for the R1109X mutation obtain a severe case of the neuropathy, while those who are heterozygous for the mutation R954X suffer from a mild case of mononeuropathy that is correlated to carpel tunnel syndrome, according to studies presented by OMIM. This provided sufficient evidence to determine who will end up receive which disease and to what extent. Individuals who are haploinsufficient of the SH3TC2 gene will have a higher tendency to suffer from carpal tunnel syndrome.

    Sources:
    -Campana, Wendy Marie. SCHWANN CELLS: ACTIVATED PERIPHERAL GLIA AND THEIR ROLE IN NEUROPATHIC PAIN.
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219463/
    PMCID: PMC2219463
    -Tiller, George E. SH3 DOMAIN AND TETRATRICOPEPTIDE REPEAT DOMAIN 2; SH3TC2. http://www.ncbi.nlm.nih.gov/omim/608206
    PMID: 608206

  28. Charcot-Marie-Tooth disease is a inherited neurological disorder, which affects the peripheral nervous system; weakening muscles. One of the notable causes of CMT is the mutation in the gene SH3TC2, SH3TC2 is a gene that is responsible for the coding of a protein expressed in the Schwann cells of the peripheral nervous system, this slight change in one of the nucleotides takes place in the glial cell in the peripheral nervous system. Schwann cells form insulation called myelin sheath, which helps increase the transfer of impulses from neuron to neuron, but as there is a decrease in the amount of myelin sheath; there is a lack of sensation and response to body function and muscle control. The effects of this disease will slowly start to be apparent in the lower limbs, and work its way up through the rest of the body, at this point no major cure is found, but intensive physical therapy could be used to aid the recovery process.

    • I found it interesting how you mentioned that physical therapy could help recovery of people with CMT disease. I wonder what types of physical therapy is necessary and to what extent it works. I was thinking maybe people who may be at risk of getting this disease could start physical therapy treatment before possibly getting diagnosed.

    • i also find it interesting you mentioned physical therapy as a hopeful aid in this disease. It does make sense that since the limbs are being weakened it would be beneficial to try and work those muscles back to a higher strength.

  29. The Charcot-Marie Tooth disease (CMT) is a genetic disorder which affects the peripheral nervous system which is needed for sensation throughout the body and all types of body movement. CMT is said to be strongly linked to the gene Sh3Tc2 which is found on chromosome 5. This gene normally has a protein that promotes myelination of the nerves which basically creates a sheath for the axons of the peripheral nervous system. Without the myelin sheath, there is nothing to insulate the axons while communication with other nerves take place and that can cause a ‘shorting out’ of these nerves and eventually they will no longer communicate. The PNS nerves are in serious risk with the occurrence of demyelination .
    The Sh3Tc2 gene undergoes many mutations in the genome sequence which leads to different proteins with different roles to play in the human body. Not all of these mutations become active because even with these mutations in play, some other genes has to be turned off because of the simple fact that cells only take one function which is assigned to them from that active gene. 19 of these mutations are said to lead to the CMT disease. If any one of these are activated from a mutated version of the genome, let’s just say that the PNS nerves are really in for it.

      • Your post was very informative and concise. I like how you explained the myelin sheath cell as something to insulate the axons. Without this the signals would not be transferred properly and a loss of function would follow. It would have been better if you had explained what kind of 19 mutation leads to the disease. Other than that, you did a great job with the descriptions.

  30. The SH3TC2 gene is found on chromosome 5 and encodes the protein expressed in Schwann cells of the peripheral nerves. When a mutation in this gene occurs, typically people develop Charcot-Marie Tooth disease (CMT). CMT is a disease that promotes atrophy of limbs and body parts of the peripheral nervous system. The peripheral nervous system is any part of the body not associated with the central nervous system, ie anything outside of the brain and spinal cord. Typically this disease weakens the muscles in legs, feet, hands and forearms.
    Schwann cells, are very important to the function of our peripheral system because they provide support, nerve development, and conduct nerve impulses through our axons. All of which keep our bodies functioning. Therefore when there is a mutation effecting these cells it causes a massive amount of problems in our development and function of specific needed limbs of our bodies.

    • I really like your explanation of the disease. It was through and understandable ( much better than mine i can assure you). However i wish you could have explained what was the reason for the loss of the PNS specifically the myelin sheath since that was the situation with CMT. I understood what happened but not the background behind it.

  31. Charcot-Marie Tooth is an inherited neurological disorder that causes one to have a loss of muscle tissue and touch sensation. This also means that muscles become weakened and one is unable to sense feeling as much in these places where muscle tissue has been lost due to the effects of the peripheral sense. The SH3TC2 gene is gives off a protein for peripheral nerves and has 18 exons ( but most of the mutations happen on exon 11). This SCH3TC2 is located on chromosome. This may mean that it can affect functions in the myelin, especially because it can affect other proteins that it interacts with. In fact, the interaction between the Schwann cell and the axon may cause a wrong myelin formation. Because the myelin is formed abnormally, the axons have an inability to communicate properly with other nerves. The SH3TC2 affect and disrupt several parts of the endocytic and membrane pathways which may lead to CMT disease.
    The clones of SH3TC2 was mainly expressed in parts of the brain rather than other parts in the brain such as lungs, livers, etc. showing that it is a neuronal disease.

    • Good response. This was a well developed piece including specific information concerning the CMT disease.

  32. Charcot-Marie-Tooth (CMT) disease that causes damage to the the nerve fibers in the body. Some forms of the disease causes the myelin sheath to be destroyed and other forms cause the central axon to wither away and weaken. This causes loss of communication or delayed reaction with the furthest parts of the body mainly the hands and feet. CMT is a very common inherited disease and affects the peripheral nerves, the ones used for movement are the ones most affected by the disease. There can be defects in about 14 different genes (one of them being the SH3TC2 gene) causing different types of the disease making cases differ from each other.

    • It is clear that CMT is a very debilitating disease, and it seems like you included what exactly CMT does, but I would also like to know, how CMT causes these detrimental effects such as how exactly the myelin sheaths are destroyed.

  33. almost forgot to put my sources
    Sources:
    “Charcot-Marie-Tooth Disease – PubMed Health.” Web. 07 Apr. 2011. .

    “Charcot-Marie-Tooth Disease Fact Sheet.” National Institute of Neurological Disorders and Stroke (NINDS). Web. 07 Apr. 2011. .

  34. The SH3TC2 gene contains 18 exons and is mapped on the chromosome number 5. It encodes a protein that is expressed in Schwann cells of peripheral nerves. It’s generally located anywhere from the plasma membrane to the perinuclear endocytic compartment. Researchers assume that the function of the gene has to do with mylienation and axoglial interactions.

    The SH3TC2 gene is said to have MANY different mutations. One of them is myristoylation, which is an irreversible protein modification. R954X and R1109X are mutuations that “caused a stop codon and produced premature truncations removing most of the C-terminal TPR domains resulted in an expression pattern that was the same as the wildtype protein. Mutations also lead to the pathogenesis of CMT4C disease, and thus impairing communication between Schawnn cells and the axon, causing abnormal myelin formations. In another family that was tested, they recorded mutations resulting in a loss of function, had a subtle mild mononeuropathy of the median nerve (MNMN; 613353) consistent with carpal tunnel syndrome. In the same family, two other members had autosomal dominant patchy axonal polyneuropathy, as shown by their electrophysiologic studies., with definite median-nerve mononeuropathy at the wrist associated with evidence of a more widespread axonal neuropathy.

    • I like how you provided a few examples of the different mutations that could happen to the SH3TC2 gene. I feel that you could gave given more details as what actually happens in each one of the mutations. The explanation that you gave was a bit confusing as I was thrown off when I read “premature truncations removing most of the C-terminal TPR domains. ” If it was described, your post would have been made better.

  35. Charcot Marie Tooth Neuropathy is an autosomal recessive disease that causes muscular atrophy and reduced nerve conductivity. It was found that a gene called the SH3TC2 gene was the major cause of the disease. A mutation in the SH3TC2 gene would disrupt the production of the SH3TC2 protein, thus making short or unstable versions of the protein.
    A recent experiment on mice showed that mice with a mutated SH3TC2 gene had a decreased motor and sensory nerve conduction. It was found that the SH3TC2 is expressed in Schwann cells and interacts with the small guanosine triphosphatase Rab11. Rab11 regulates internal membranes and receptors to a cell’s surface. The SH3TC2 gene and the Rab11 are both involved with Schwann cell myelination. With a mutated SH3TC2 gene, the Rab11 is forced to disrupt proper formation myelin formation. Because myelin increases a nerve signal, disrupted formation of myelin causes slower nerve reactions in the body.

  36. The SH3TC2 gene is localized in the plasma membrane and the perinuclear endocytic recycling compartment, where myelination and/or in regions of axoglial interactions occur. The SH3TC2 gene is responsable for encoding a protein with two N-terminal Src homology 3 (SH3) domains and 10 tetratricopeptide repeat (TPR) motifs. Schwann cells expresse the orthologue version of this gene that finds the plasma membrane and the perinuclear endocytic recycling compartment in the gene. These locations have a consistent with a role in myelination and/or axion, a glial cell interactions. Mutations in this gene result in autosomal recessive Charcot-Marie-Tooth disease type 4C, a childhood-onset neurodegenerative disease characterized by demyelination of motor and sensory neurons. The SH3TC2 protein is present in several components of the endocytic pathway including early endosomes, late endosomes and clathrin-coated vesicles close to the trans-Golgi network and in the plasma membrane.

  37. Charcot-Marie-Tooth (CMT) disease is a series of hereditary diseases that targets the central nervous system and the peripheral nervous system. In the article, “Whole Genome Sequencing in a Patient with Charcot-Marie-Tooth Neuropathy”, it was determined that a mutation within the SH3TC2 gene, and it’s actions, plays a vital role in the Charcot-Marie-Tooth disease. The SH3TC2 gene is located on chromosome number 5, and is expressed in only schwann cells. These cells aid in the status of axons (nerve cells). Axons send electrical impulses throughout the body to communicate without cells, whether they are other nerve cells or muscle cells. In the case of Charcot-Marie-Tooth disease, the mutation in the SH3TC2 gene causes the myelin sheath to deteriorate, leaving nerve cells and nerve impulses unprotected. As a result, the neuronal cells have great difficulty communicating with other cells throughout the body. This, in turn, causes muscle weakness, loss in muscle control or atrophy.

    • I liked the fact that you kept it concise and in an understandable tone. You didn’t use confusing terms that continuously needed to be defined. However i wish that you went into a little more detail about the mutation itself.

  38. The locus of SH3TC2 is 5q32 which means that it is located on chromosome number 5. The SH3TC2 gene makes proteins that will be expressed in Schwann cells of peripheral nerves. The gene helps myelin sheaths wrap around nerves and helps support the Peripheral Nervous System. The gene is localized in the plasma membrane and the perinuclear endocytic recycling compartment. As for the gene structure of SH3TC2 it contains 18 exons.
    The Charcot-Marie-Tooth disease is an inherited disease that affects the peripheral nerves in the body. Through testing it appears that the cause of this disease is mutations on the gene SH3TC2. This disease is very debilitating because it affects the sensory cells and muscles of the body. The peripheral muscles connect the brain and the spinal cord. This disease ultimately wears away at the myelin sheaths around the nerves. It most notably affects the hands and feet of those affected. Their hands and feet may become deformed and they loss sensation in their limbs as well.

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