Case of a mentally retarded child with non-24 hour sleep-wake syndrome caused by deficiency of melatonin secretion

Abstract

A case of a 5-year-old boy with non-24 hour sleep-wake syndrome and mental retardation is reported. His free-running sleep-wake rhythm was remarkably improved by the oral administration of melatonin. The circadian variation in melatonin secretion was extremely low, and circadian rhythm of cortisol secretion was noted. It was speculated that his non-24 hour sleep- wake syndrome was due to a congenital deficiency of melatonin secretion, and supplemental melatonin therapy proved effective for treating his condition.