Infantile neuroaxonal dystrophy is a disease entity first described by Seitelberger in 1952. Since then eight cases have been reported. In spite of extensive pathologic and clinical descriptions the exact nature of the lesions is not yet defined, and the classification of this nosologic entity is still not clear. The following case report differs in some respects from those previously reported and thus may add to our knowledge concerning this disease. Report of Case A 3-year-old male infant was admitted to the pediatric department for evaluation because of mental retardation and severe generalized muscle hypotonia. He was born after an uneventful pregnancy and delivery. The birth weight was 4,200 gm (9 lb). His parents were healthy and were not related. No neurologic diseases were noted in the family. He was the only child. At the age of 1 year his parents noted an arrest in his motor and mental