[Ethnic variation in congenital pigmentation anomalies]

Abstract

Clear ethnic differences are observed in the major form of tyrosinase-negative oculocutaneous albinism as well as in other forms of oculocutaneous albinism, cutaneous albinism and the very rare ocular albinism. Most interesting is the borderline between normal variation and abnormal forms, especially illuminated in rutilism or red headedness in Negroids and high frequencies of pigmentation anomalies without appreciable disadvantages for the carrier, e.g., the reddish skin of geographically isolated Papuans. The very differential frequencies of the occurrence of pigmentation anomalies in some populations are influenced as well by population genetic factors (isolation/inbreeding, founder-effect, heterosis) as also by socio-cultural factors (albinism as a marriage barrier, infanticide), and in some areas perhaps some kind of negative selection in which individuals with the character in question fail to reach reproductive age.