Hypomelanosis of Ito.

Hypomelanosis of Ito appears to be a disorder of hypopigmentation. Findings from histochemical and electronmicroscopic studies indicate that pigment cells from the hypopigmented areas have short dendrites and synthesize less than normal amounts of melanin. The syndrome may have two forms; a cutaneous and neurocutaneous variety. In the more severe neurocutaneous variety, the phenotypic pigmentary abnormalities probably reflect a biochemical defect in all tissues derived from the neuro-ectodermal anlage.