True human piebaldism is a rare disorder. Piebaldism involves distinct patches of skin and hair that contain no pigment. Melanocytes are completely lacking in these hypopigmented regions. Surrounding skin and hair show normal pigmentation. Piebaldism often presents as a white forelock of scalp hair, but patches of depigmented hair or skin can occur anywhere on the body and there may be more than one affected area. The difference is that piebaldism is a genetic abnormality that affects a single, specific gene.