Charcot-marie-tooth Disease, Demyelinating, Type 1b; Cmt1b

Description

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. ClassificationOn 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 (OMIM ) 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 (OMIM ), CMT2A1 (OMIM ), CMT3 (DSS ), CMT4A (OMIM ), and CMTDIB (OMIM ). Genetic Heterogeneity of Autosomal Dominant Demyelinating CMT1Autosomal dominant demyelinating CMT1 is genetically heterogeneous disorder and can be caused by mutations in different genes (see CMT1A, {118220}; CMT1C, {601098}; CMT1D, {607678}), CMT1E (OMIM ), and CMT1F (OMIM ). See also {608236} for a related phenotype characterized by isolated slowed nerve conduction velocities (NCVs).

Clinical Features

Top most frequent phenotypes and symptoms related to Charcot-marie-tooth Disease, Demyelinating, Type 1b; Cmt1b

  • Hearing impairment
  • Ataxia
  • Muscle weakness
  • Pain
  • Peripheral neuropathy
  • Skeletal muscle atrophy
  • Optic atrophy
  • Tremor
  • Cardiomyopathy
  • Blindness

And another 40 symptoms. If you need more information about this disease we can help you.

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Incidence and onset information

Not enough data available about incidence and published cases.
No data available about the known clinical features onset.

Alternative names

Charcot-marie-tooth Disease, Demyelinating, Type 1b; Cmt1b Is also known as hmsn1b, charcot-marie-tooth neuropathy, type 1b, charcot-marie-tooth disease, autosomal dominant, with focally folded myelin sheaths, type 1b, hereditary motor and sensory neuropathy ib, hereditary motor and sensory neuropathy i, hmsn i, peroneal muscular atrop.

Researches and researchers

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Charcot-marie-tooth Disease, Demyelinating, Type 1b; Cmt1b Recommended genes panels

Panel Name, Specifity and genes Tested/covered
CMT Advanced Evaluation - Dominant.

By Athena Diagnostics Inc (United States).

YARS, LITAF, MFN2, TRPV4, DNM2, HSPB8, EGR2, GARS, HSPB1, MPZ, NEFL, PMP22, RAB7A
Specificity
8 %
Genes
100 %
CMT Advanced Evaluation - Dominant, Demyelinating.

By Athena Diagnostics Inc (United States).

YARS, LITAF, DNM2, EGR2, MPZ, PMP22
Specificity
17 %
Genes
100 %
CMT Advanced Evaluation - Dominant, Axonal.

By Athena Diagnostics Inc (United States).

YARS, MFN2, TRPV4, DNM2, HSPB8, GARS, HSPB1, LMNA, MPZ, NEFL, RAB7A
Specificity
10 %
Genes
100 %
CMT Advanced Evaluation - Comprehensive.

By Athena Diagnostics Inc (United States).

YARS, PRX, GDAP1, LITAF, FIG4, MFN2, TRPV4, FGD4, SBF2, SH3TC2, DNM2, HSPB8, EGR2, GARS, GJB1, HSPB1, LMNA, MPZ, MTMR2, NDRG1 , (...)

View the complete list with 3 more genes
Specificity
5 %
Genes
100 %
CMT Advanced Evaluation - Axonal.

By Athena Diagnostics Inc (United States).

YARS, GDAP1, MFN2, TRPV4, DNM2, HSPB8, GARS, GJB1, HSPB1, LMNA, MPZ, NEFL, RAB7A
Specificity
8 %
Genes
100 %
CMT Advanced Evaluation - Demyelinating.

By Athena Diagnostics Inc (United States).

YARS, PRX, GDAP1, LITAF, FIG4, FGD4, SBF2, SH3TC2, DNM2, EGR2, GJB1, MPZ, MTMR2, NDRG1, PMP22
Specificity
7 %
Genes
100 %
MPZ DNA Sequencing Test.

By Athena Diagnostics Inc (United States).

MPZ
Specificity
100 %
Genes
100 %
Congenital Hypomyelination Evaluation.

By Athena Diagnostics Inc (United States).

EGR2, MPZ
Specificity
50 %
Genes
100 %

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Sources and references

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OMIM Rare Disease Search Engine

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