A genetic disease that begins soon after birth with the development of blisters on the trunk and limbs.

These blisters then heal, but leave dark hyperpigmented streaks and marble-like whorls on the skin. Other key features include dental and nail abnormalities, bald patches and, in about one-third of cases, mental retardation.

The name came from the erroneous idea that the skin cells were incontinent of pigment and could not contain it normally.