Precocious puberty and decreased melatonin secretion due to a hypothalamic hamartoma.

Hypothalamic hamartomata are benign malformations of the brain consisting of heterotopic nervous tissue, and are often associated with precocious puberty and gelastic seizures in early childhood. We report for the first time the melatonin plasma values of a girl with central precocious puberty and gelastic seizures due to a hypothalamic hamartoma. The melatonin plasma levels were low for the chronological age but appropriate for the pubertal status, making a causal relationship between lowered melatonin plasma levels and precocious puberty possible.