[A case of adrenomyeloneuropathy with marked spinal cord atrophy on magnetic resonance imaging].

A 29-year-old man complained of increasing paraplegia and sphincter disturbances. On admission, he was 23 years old. He had moderate pigmentation of the skin, and his neurological examinations revealed spastic paraplegia, hyperreflexia of both legs with Babinski's signs, a pinprick sensation deficit below the L-1 level, loss of vibration sense in the lower extremities and horizontal nystagmus on lateral gaze. Endocrinological examinations revealed adrenocortical insufficiency. CSF, EEG, EMG, brain-CT and myelography did not show any abnormalities, but metrizamide CT myelography at the low thoracic spinal cord revealed decreased cord diameter. Nerve conduction velocities showed impairment in the tibial and peroneal motor fibers. Auditory brain-stem response revealed elongated III-V interval. A cystometrogram disclosed a reflex neurogenic bladder. In the analysis of the fatty acid component of plasma sphingomyelin, the C26/C22, C25/C22, C24/C22 ratios were found to be increased, and the diagnosis of adrenomyeloneuropathy (AMN) was confirmed. The patient's mother was also found to be asymptomatic carrier of AMN on the basis of long chain fatty acid plasma levels. The MRI performed in his age of 29 years, showed marked spinal atrophy from low cervical to low thoracic regions and mild cerebellar atrophy. This findings seems to correspond with chronic progressive demyelination of spinal white matter such as pyramidal tract and fasciculus gracilis.