A Case of Motor and Sensory Neuropathy Associated with Metatropic Dysplasia

Abstract

We reported a case of a fifteen-year-old boy with metatropic dysplasia. He showed short-limbed dwarfism at the age of 1 year and 2 months. Roentgenograms of the bone revealed generalized platyspondyly, enlargement of the epiphyseal-metaphyseal regions of long bones and halberd- shaped pelvis. Scoliosis progressed and he evolved to short-trunk dwarfism. When he was 10 years old, he developed gait disturbance gradually due to muscle weakness of lower extremities. He was examined at the age of 15 years. Motor nerve conduction velocity was reduced to 21 m/sec in left median nerve and 18.5 m/sec in left peroneus nerve. Needle EMG showed neurogenic pattern. We performed sural nerve biopsy and obtained histopathological findings. Fiber density of myelinated axons decreased. Electron microscopic examination revealed onion bulb formation surrounding a myelinated fiber and a storage in the rough-surfaced endoplasmic reticulum of Schwann cell. These inclusions were similar to those of cartilage of his long bone. We supposed that the neuropathy would have relation to this bone dysplasia.