Peripheral neuropathy in classic Niemann-Pick disease: ultrastructure of nerves and skeletal muscles.

A patient with classic (type A) Niemann-Pick disease had the usual clinical signs of failure to thrive, hepatosplenomegaly, and intellectual deterioration in the first year of life. In addition, there was striking hypotonia, areflexia, and abnormal nerve conduction velocities. Pathologically, the Schwann cells were filled with numerous cytoplasmic bodies. These bodies measured 1 mu in diameter and appeared to be dense, round masses with poorly defined internal structure but with occasional slightly curved parallel lines and small radiolucent areas. Peripheral nerve involvement may be a frequent finding in patients with classic Niemann-Pick disease.