Search for a rare disease

* (*) mandatory field

Other search option(s)

Suggest an update

(*) Required fields.


Only comments seeking to improve the quality and accuracy of information on the Orphanet website are accepted. For all other comments, please send your remarks via contact us. Only comments written in English can be processed.

Orphanet doesn't provide personalised answers. To get in touch with the Orphanet team, please contact

Information provided in your contribution (including your email address) will be stocked in .CSV files that will be sent as an email to Orphanet's teams. These emails might be conserved in the teams' mailboxes, in our backoffice servers but will not be registered in our databases (for more information see our section General Data Protection Regulation and data privacy (GDPR) and Confidentiality).

Captcha image

Charcot-Marie-Tooth disease type 4B1

Disease definition

Charcot-Marie-Tooth disease type 4B1 (CMT4B1) is a subtype of Charcot-Marie-Tooth disease type 4 characterized by an early childhood-onset of severe, demyelinating sensorimotor neuropathy, various degrees of complex myelin outfoldings seen on peripheral nerve biopsy, very slow, and often undetectable, nerve conduction velocities, and the typical CMT phenotype (i.e. distal muscle weakness and atrophy, sensory loss, and frequent pes cavus). Other reported features include facial weakness, vocal cord paresis, respiratory difficulties, and skeletal deformities (e.g. chest deformities, claw hands, pes equinovarus).


Classification level: Disorder
  • Synonym(s):
    • CMT4B1
  • Prevalence: <1 / 1 000 000
  • Inheritance: Autosomal recessive 
  • Age of onset: Infancy, Neonatal
  • ICD-10: G60.0
  • OMIM: 601382
  • UMLS: C1832399
  • MeSH: C535420
  • GARD: 1253
  • MedDRA: -

Detailed information

Article for general public


The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care by a qualified specialist and should not be used as a basis for diagnosis or treatment.