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References OMIM Gene GeneReviews HGMD HGNC
last update : 25-08-2014
Symbol CMT2B
Location 3q21.3
HGNC id 2132
Name Charcot-Marie-Tooth disease, axonal, type 2B
Other name(s)
  • Charcot-Marie-Tooth neuropathy type 2B
  • hereditary motor and sensory neuropathy IIB
  • Corresponding gene RAB7A
    Other symbol(s) HSAN5, PSAN, PSN
    Main clinical features
  • axonal, with normal motor conduction velocity, may be an hereditary sensory and autonomic neuropathy type 1, ulcero-mutilating neuropathy, developing in the teens and characterized by ulcers, amputations, sensory involvement in the feet but no motor features, common ulcerations and amputations and moderatly slowed motor nerve conduction velocities
  • Genetic determination autosomal dominant
    Function/system disorder neurology
    Type disease
    Gene mutationChromosome rearrangementEffectComments
    various types   abnormal protein/gain of function  
  • hotspot for mutations in the highly conserved C terminus of RAB7
  • Rab7 K157N showed altered nucleotide exchange rate and GTP hydrolysis compared to the wild type protein and in addition, have ability to restore EGF degradation, previously inhibited by RAB7 silencing
  • RAB7A CMT2B mutants impair epidermal growth factor receptor degradation, alter endosomal MAPK signaling, and down-regulate FOS and EGR1 expression (PMID: 23188822))