Differences between hereditary motor and sensory neuropathy type 2 and chronic idiopathic axonal neuropathy. A clinical and electrophysiological study.

To evaluate whether chronic idiopathic axonal polyneuropathy (CIAP) should be considered as hereditary motor and sensory neuropathy type 2 (HMSN type 2), we compared the clinical features of 48 patients with CIAP with those of 47 patients with HMSN type 2. In addition, we studied electrophysiological data in 20 patients with CIAP and in 20 patients with HMSN type 2. We found, in patients with HMSN type 2, that the initial symptoms were predominantly motor and that weakness and handicap were more severe and skeletal deformities more frequent, compared with those of CIAP patients. Electrophysiologically, the tibialis anterior muscle showed more denervation in patients with HMSN type 2, consistent with the predominance of motor symptoms. There was no important effect of age of onset on clinical features in HMSN type 2 patients. We conclude that in an individual patient with a sensory or sensorimotor idiopathic axonal polyneuropathy and no family history of polyneuropathies, the diagnosis HMSN type 2 is unlikely. However, if motor symptoms predominate, the diagnosis of HMSN type 2 should be considered.