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GTR Home > Conditions/Phenotypes > Charcot-Marie-Tooth disease type 1B

Charcot-Marie-Tooth disease type 1B

Synonyms
CHARCOT-MARIE-TOOTH DISEASE, AUTOSOMAL DOMINANT, WITH FOCALLY FOLDED MYELIN SHEATHS, TYPE 1B; CHARCOT-MARIE-TOOTH DISEASE, SLOW NERVE CONDUCTION TYPE, LINKED TO DUFFY; CHARCOT-MARIE-TOOTH NEUROPATHY, TYPE 1B; Charcot-Marie-Tooth disease, demyelinating, type 1b; Charcot-Marie-Tooth disease, type IB; HEREDITARY MOTOR AND SENSORY NEUROPATHY I; HEREDITARY MOTOR AND SENSORY NEUROPATHY IB; Hereditary motor and sensory neuropathy 1B; PERONEAL MUSCULAR ATROPHY
Modes of inheritance
Autosomal dominant inheritance (Orphanet)

Summary

Charcot-Marie-Tooth disease is a sensorineural peripheral polyneuropathy. Affecting approximately 1 in 2,500 individuals, Charcot-Marie-Tooth disease is the most common inherited disorder of the peripheral nervous system (Skre, 1974). Autosomal dominant, autosomal recessive, and X-linked forms have been recognized. Classification On the basis of electrophysiologic properties and histopathology, CMT has been divided into primary peripheral demyelinating (type 1, or HMSNI) and primary peripheral axonal (type 2, or HMSNII) neuropathies. The demyelinating neuropathies classified as CMT type 1 are characterized by severely reduced motor NCVs (less than 38 m/s) and segmental demyelination and remyelination with onion bulb formations on nerve biopsy. The axonal neuropathies classified as CMT type 2 are characterized by normal or mildly reduced NCVs and chronic axonal degeneration and regeneration on nerve biopsy (see CMT2A1; 118210). Distal hereditary motor neuropathy (dHMN) (see 158590), or spinal CMT, is characterized by exclusive motor involvement and sparing of sensory nerves (Pareyson, 1999). McAlpine (1989) proposed that the forms of CMT with very slow nerve conduction be given the gene symbol CMT1A (118220) and CMT1B, CMT1A being the gene on chromosome 17 and CMT1B being the gene on chromosome 1. CMT2 was the proposed symbol for the autosomal locus responsible for the moderately slow nerve conduction form of the disease (axonal). For a phenotypic description and discussion of genetic heterogeneity of the various subtypes of CMT, see CMTX1 (302800), CMT2A1 (118210), CMT3 (DSS; 145900), CMT4A (214400), and CMTDIB (606482). Genetic Heterogeneity of Autosomal Dominant Demyelinating CMT1 Autosomal dominant demyelinating CMT1 is a genetically heterogeneous disorder and can be caused by mutations in different genes; see CMT1A (118220), CMT1C (601098), CMT1D (607678), CMT1E (607734), CMT1F (607734), CMT1G (618279), CMT1H (619764), CMT1I (619742), and CMT1J (620111). See also 608236 for a related phenotype characterized by isolated slowed nerve conduction velocities (NCVs). [from OMIM]

Available tests

60 tests are in the database for this condition.

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Clinical tests (60 available)

Molecular Genetics Tests

Genes See tests for all associated and related genes

  • Also known as: CHM, CHN2, CMT1, CMT1B, CMT2I, CMT2J, CMT4E, CMTDI3, CMTDID, DSS, HMSNIB, MPP, P0, MPZ
    Summary: myelin protein zero

Clinical features

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Imported from Human Phenotype Ontology (HPO)

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Reviews

Clinical resources

Practice guidelines

  • EuroGenetest, 2010
    Clinical utility gene card for: HMSN/HNPP HMSN types 1, 2, 3, 6 (CMT1,2,4, DSN, CHN, GAN, CCFDN, HNA); HNPP

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