[Congenital sensory neuropathy with anhidrosis: type IV. Apropos of 2 new cases].

Two new cases of congenital sensory neuropathy (CSN) type IV in brothers aged 10 and 5 years are reported. Features included diffuse lack of response to pain without loss of response to touch, temperature and proprioceptive stimuli. No other neurologic anomalies were found. Both patients had complete anhidrosis. Joint destruction, which was the result of the failure to react to painful stimuli, was the most prominent feature. Nerve biopsy specimens exhibited marked reductions in numbers of amyelinic fibers with normal numbers of myelinic fibers. These two cases of CSN type IV are discussed in the light of previously reported cases and the new classification of congenital sensory neuropathies is reviewed.