The synthesis of melanin is ubiquitous in the animal kingdom and is under complex genetic control. Inborn errors of melanin formation, as with other inborn errors of metabolism, provide models to explore this genetic control. Human OCA is a fascinating group of disorders of melanin formation, and careful analysis of each type allows the development of hypothesis on probable mechanisms of development. The broader category of mild to moderate hypopigmentation without all of the features of albinism may ultimately prove to be as important in understanding melanin metabolism.