CLINICAL AND GENETIC STUDIES IN PATIENTS WITH HEREDITARY MOTOR SENSORY NEUROPATHY TYPE Ⅰ

We investigated 12 Japanese patients whose diagnosis was hereditary motor sensory neuropathy type Ⅰ (HMSN Ⅰ) from clinical and pathological findings. We compared the genetic findings with their clinical features, MRI findings of the nerve roots, nerve biopsy findings, electrophysiological studies, and magnetic stimulation studies. So far as we investigated, PMP-22 gene duplication was detected in one half of the patients while no genetic changes of PMP-22 or P0 were observed in the other. Enlargement of peripheral nerves and nerve roots was remarkable in patients without abnormalities of PMP-22 or P0, while some of them showed signs of radiculopathy or myelopathy. In patients with PMP-22 gene duplication, there was a significant correlation between the age at onset and MCV. This fact indicated that patients with younger onset and slower MCV had more severe symptoms. Though HMSN Ⅰ is thought to be heterogeneous, we could detect significant features between clinical and electrophysiological findings according to the analysis of PMP-22 duplication