Hypomelanosis of Ito and precocious puberty.

We describe two girls with hypomelanosis of Ito, one of whom was demonstrated to have diploid-triploid mixoploidy in skin fibroblasts. Both had precocious puberty which was probably gonadotrophin-independent. The association of precocious puberty and hypomelanosis of Ito has not been previously reported. We have speculated on the possible mechanism of gonadotrophin-independent precocious puberty.