View source for Charcot-Marie-Tooth disease classification

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{{Charcot-Marie-Tooth disease}}
{{CMG}}
==Overview==

== Classification ==

* CMT Type 1 (CMT1): Type 1 affects approximately 80% of CMT patients and is the most common type of CMT. The subtypes share clinical symptoms. [[Autosomal dominant]]. Causes demyelination, which can be detected by measuring [[nerve conduction velocities]].

* CMT Type 2 (CMT2): Type 2 affects approximately 20-40% of CMT patients. Type 2 CMT is [[Autosomal dominant]] neuropathy  with its main effect on the axon. The average [[nerve conduction velocity]] is slightly below normal, but generally above 38 m/s

* CMT Type 3 (CMT3): Type 3 affects a very few CMT patients.

* CMT Type 4 (CMT4): Type 4 affects a very few CMT patients.

* CMT X-Linked (CMTX): CMTX affects approximately 10-20% of CMT patients and is [[Dominant gene|X-linked dominant]]. Approx 10% of X-linked CMT patients have some other form than CMTX.

More details on the types are provided in the table below:

{| class="wikitable"
| '''Type''' || '''[[OMIM]]''' || '''Gene ''' || '''[[Locus (genetics)|Locus]]'''  || '''Description'''
 |- 
 |  CMT1A  || {{OMIM2|118220}} || {{Gene|PMP22}}  || 17p11.2  ||  The most common form of the disease, 70-80% of Type 1 patients.  Average [[Nerve conduction velocity|NCV]]: 15-20 m/s  when associated with essential [[tremor]] and [[ataxia]], called [http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=180800 Roussy-Levy Syndrome]
 |- 
 |  CMT1B || {{OMIM2|118200}}   || {{Gene|MPZ}}  || 1q22  ||  Caused by mutations in the gene producing protein zero (P0). 5-10% of Type 1 patients. Average [[Nerve conduction velocity|NCV]]: <20 m/s
 |- 
 |  CMT1C  ||   || {{Gene|LITAF}}  || 16p13.1-p12.3  ||  Causes severe [[myelin|demyelination]], which can be detected by measuring nerve conduction velocities.  [[Autosomal dominant]]. Usually shows up in infancy. Average [[Nerve conduction velocity|NCV]]: 26-42 m/s. Identical symptoms to CMT-1A.
 |- 
 |  CMD1D  ||   || {{Gene|EGR2}}  || 10q21.1-q22.1  ||  Average [[NCV]]: 15-20 m/s
 |- 
 |  CMT2A || {{OMIM2|118210}} || {{Gene|MFN2}} or {{Gene|KIF1B}}  || 1p36  ||  The cause is likely located on chromosome 1 for the mitofusion 2 protein. Some research has also linked this form of CMT to the protein kinesin 1B. Does not show up on [[nerve conduction velocity]] tests, because it is caused by axonopathy.
 |- 
 |  CMT2B || {{OMIM2|600882}} || RAB7 ({{Gene|RAB7A}}, {{Gene|RAB7B}})  || 3q21.  || 
 |- 
 |  CMT2B1 ||   || {{Gene|LMNA}}  ||  1q22 || [[Autosomal recessive]] axonal CMT, ([[Laminopathies|laminopathy]])
 |- 
 |  CMT2C  || {{OMIM2|606071}}  ||   || 12q23-q24  ||  May cause vocal cord, [[diaphragm]], and distal [[weakness]]es.
 |- 
 |  CMT2D || {{OMIM2|601472}}   || {{Gene|GARS}}  || 7p15  || Patients with mutations in the GARS gene tend to have more severe symptoms in the upper extremities (hands), which is atypical for CMT in general.
 |- 
 |  CMT2E  ||   || {{Gene|NEFL}}  || 8p21  || 
 |- 
 |  CMT2F || {{OMIM2|606595}}   || {{Gene|HSPB1}}  || 7q11-q21  || 
 |- 
 |  CMT2G  || {{OMIM2|608591}}  ||   || 12q12-13  || 
 |- 
 |  CMT2H || {{OMIM2|607731}}   || {{Gene|GDAP1}}  ||  8q13-q21.1 || 
 |- 
 |  CMT2J || {{OMIM2|607736}}   ||   || 1q22  || 
 |- 
 |  CMT2K || {{OMIM2|607831}}   ||   || 8q13-q21.1  || 
 |- 
 |  CMT2L || {{OMIM2|608673}}   ||   || 12q24  || 
 |- 
 |  CMT3  || {{OMIM2|145900}}  ||  varies || varies  ||  Sometimes called [[Dejerine-Sottas disease]]. Rarely found. [[Autosomal recessive]]. Average [[Nerve conduction velocity|NCV]]: Normal (50-60m/s)
 |- 
 |  CMT4A || {{OMIM2|214400}}   || {{Gene|GDAP1}}  || 8q13-q21.1  || [[Autosomal recessive]].
 |- 
 |  CMT4B1 || {{OMIM2|601382}}   || {{Gene|MTMR2}}  || 11q22  || [[Autosomal recessive]].
 |- 
 |  CMT4B2  ||   ||  CMT4B2 ({{Gene|SBF2}}) || 11p15  || May be called "SBF2/MTMR13". [[Autosomal recessive]].
 |- 
 |  CMT4C  ||   ||  KIAA1985 ({{Gene|SH3TC2}}) || 5q32  ||  May lead to respiratory compromise.
 |- 
 |  CMT4D  || {{OMIM2|601455}} ||  {{Gene|NDRG1}}  || 8q24.3  || [[Autosomal recessive]], [[demyelinating]], [[deafness]] 
 |- 
 |  CMT1E  || {{OMIM2|118300}}   || {{Gene|PMP22}}  || 17p11.2  || [[Autosomal dominant]], [[demyelinating]], [[deafness]]
 |- 
 |  CMT4E  ||   ||  {{Gene|EGR2}}   || 10q21.1-10q22.1  ||  "CMT4E" is a tentative name
 |- 
 |  CMT4F  ||   ||  {{Gene|PRX}}   || 19q13.1-19q13.2  ||  "CMT4F" is a tentative name
 |-
 |  CMT4J  || {{OMIM2|611228}}  || KIAA0274 ({{Gene|FIG4}}) || 6q21  ||  [[Autosomal recessive]]
 |- 
 |  CMTX1  || {{OMIM2|302800}}   || {{Gene|GJB1}}  || Xq13.1  ||  Average [[Nerve conduction velocity|NCV]]: 25-40 m/s
 |- 
 |  CMTX2  || {{OMIM2|302801}}   ||  || Xq22.2  ||  
 |- 
 |  CMTX3  || {{OMIM2|302802}}   ||  || Xq26  || 
 |- 
 |   CMT   || {{OMIM2|118301}}   ||  || || with [[Ptosis]] and [[Parkinsonism]] 
 |- 
 |   CMT   || {{OMIM2|302803}}   ||  || || type 1 [[aplasia]] cutis congenita

|}



==References==
{{reflist|2}}

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