A new SBF2 mutation in a family with recessive demyelinating Charcot-Marie-Tooth (CMT4B2)

Charcot-Marie-Tooth (CMT) 1type 4 is a group of autosomal recessive progressive motor and sensory neuropathies characterized by distal muscle weakness and atrophy associated with sensory loss and, frequently, pes cavus foot deformity. CMT4 includes clinically and genetically heterogeneous disorders. Seven genes responsible for the different CMT4 subtypes (CMT4A, B1, B2, C, D, E, and F) have been identified so far.1 CMT4B, characterized by focally folded myelin sheaths on sural nerve biopsy, was first described in an Italian family2 and then in several other families of different ancestry. CMT4B is genetically heterogeneous. One form of CMT4B is caused by homozygous loss of function mutations in the myotubularin-related 2 gene (MTMR2) on chromosome 11q23 (CMT4B1).3 A second locus responsible for CMT4B has been mapped …