AFRICAN ORIGIN OF AN INTRAGENIC DELETION OF THE HUMAN-P GENE IN TYROSINASE POSITIVE OCULOCUTANEOUS ALBINISM

Oculocutaneous albinism (OCA) is a genetically heterogeneous hypopigme ntation disorder. One of the two major autosomal recessive forms invol ves the tyrosinase gene (OCA1), while the other form (OCA2) has recent ly been associated with alterations of the P gene on chromosome 15. OC A2 is about twice as common as OCA1 in African and African-American po pulations. We now describe an interstitial deletion that removes a sin gle exon of the P gene. Tn a large family from an inbred population of tri-racial origin, all individuals with OCA2 were found to be homozyg ous for this allele. Moreover, the same mutant P allele was detected i n several unrelated African American individuals with OCA2, but not in Caucasians with OCA2. The detection of the same allele in two unrelat ed Africans with OCA2 indicates an African origin for this allele.