Misclassification and linkage of hereditary sensory and autonomic neuropathy type 1 as Charcot-Marie-Tooth disease, Type 2B

Recently Kwon et al. published in the Journal their work describing linkage of a single large family with an inherited axonal neuropathy to chromosome 3, which they suggest is a second locus for Charcot-Marie-Tooth (CMT) type 2 and subsequently named {open_quotes}CMT2B.{close_quotes} We think that the diagnostic classification of this family as CMT2 is incorrect, since the subjects have a severe sensory neuropathy that fits within the hereditary sensory and autonomic neuropathy (HSAN) type 1 classification of Dyck (1993). Abnormal sensory findings in CMT2 separate it from distal spinal muscular atrophy but are a minor component of clinical symptoms in most CMT patients, as CMT is primarily a motor neuropathy. When Kwon et al. state that {open_quotes}all [patients] had characteristic findings in their physical examinations, including... evidence of foot sores that were slow to heal, or amputated limbs related to the poorly healing foot ulcers,{close_quotes} it suggests that a different diagnosis is more appropriate. In our experience collecting data on >950 individuals in >60 CMT1, CMT2, CMTX and CMT4 families, we have not seen foot ulcers, osteomyelitis, or amputations. Ulcerations leading to osteomyelitis and amputations are usually associated with severe sensory neuropathies. 16 refs., 1 tab.