<unk>  refers to the absence of mature melanin-forming cells (melanocytes) in certain areas of the skin and hair. It is a rare autosomal dominant disorder of melanocyte development. Common characteristics include a congenital white forelock, scattered normal pigmented and hypopigmented macules and a triangular shaped depigmented patch on the forehead. There is nevertheless great variation in the degree and pattern of presentation, even within affected families. In some cases,<unk>  occurs together with severe developmental problems, as in Waardenburg syndrome and Hirschsprung's disease.<unk>  has been documented to occur in all races, and is found in nearly every species of mammal. The condition is very common in mice, rabbits, dogs, sheep, deer, cattle and horses—where selective breeding has increased the incidence of the mutation—but occurs among chimpanzees and other primates only as rarely as among humans.<unk>  is unrelated to conditions such as vitiligo or poliosis. Although<unk>  may visually appear to be partial albinism, it is a fundamentally different condition. The vision problems associated with albinism are not usually present as eye pigmentation is normal.<unk>  differs from albinism in that the affected cells maintain the ability to produce pigment but have that specific function turned off. In albinism the cells lack the ability to produce pigment altogether. Human<unk>  has been observed to be associated with a very wide range and varying degrees of endocrine disorders, and is occasionally found together with heterochromia of the irises, congenital deafness, or incomplete gastrointestinal tract development, possibly all with the common cause of premature cutting off of human fetal growth hormone during gestation.<unk>  is a kind of neurocristopathy, involving defects of various neural crest cell lineages that include melanocytes, but also involving many other tissues derived from the neural crest. Oncogenic factors, including mistranscription, are hypothesized to be related to the degree of phenotypic variation among affected individuals.
Piebaldism
Hypomimia
Diabulimia
Machiavellianism
Hypertelorism
Manganism
Lathyrism
Hypnagogia