Charcot-Marie-Tooth disease type 2B2 (CMT2B2) is an autosomal recessive sensorineural axonal peripheral neuropathy manifest as distal muscle weakness and atrophy and distal sensory impairment. The disorder predominantly affects the lower limbs, resulting in gait impairment, although upper limb and hand involvement also occurs. The age at onset and severity is variable: most have onset in the third decade, although earlier onset has been reported. The disorder is slowly progressive, and some patients may lose independent ambulation later in life. More variable features may include ataxia, dysarthria, cerebellar atrophy, and eye movement abnormalities (summary by Leal et al., 2018). For a phenotypic description and a discussion of genetic heterogeneity of axonal CMT type 2, see CMT2A1 (118210). [from OMIM]

Etiology