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Charcot-Marie-Tooth disease type 4B2

Synonym(s) CMT4B2
Prevalence Unknown
Inheritance Autosomal recessive
Age of onset Childhood
  • G60.0
  • C1858278
  • C535421
MedDRA -


Disease definition

Charcot-Marie-Tooth disease, type 4B2 (CMT4B2) is a severe early-onset demyelinating CMT peripheral sensorimotor polyneuropathy.


It has been reported in families from Italy, Turkey, Tunisia, and Morocco.

Clinical description

CMT4B2 is clinically and pathologically very similar to CMT4B1 (see this term) with childhood-onset of muscle weakness, sensory loss, reduced nerve conduction velocities, characteristic myelin outfoldings and a severe disease course. However, in addition to the severe neuropathy, patients from some CMT4B2 families also develop early-onset glaucoma.


CMT4B2 is caused by mutations in the MTMR13/SBF2 gene encoding a protein involved in polyphosphoinositide signaling. Early-onset glaucoma is associated with specific nonsense SBF2 mutations and was not seen in CMT4B2 patients carrying a small in-frame SBF2 deletion.

Genetic counseling

CMT4B2 is transmitted in an autosomal recessive manner.

Expert reviewer(s)

  • Dr Carmen ESPINÓS
  • Pr Francesc PALAU

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