Geographical survey of β(S)-globin gene haplotypes: Evidence for an independent Asian origin of the sickle-cell mutation

The haplotypes of 152 β(S)-chromosomes were characterized in six different population groups. The chromosomes of individuals from Nigeria and from the southwest of the Arabian peninsula have the haplotype ----+ +-+ previously found in west African, Jamaican, and U.S. American blacks, whereas those from the eastern oases of Saudi Arabia and from the west and the east coast of India showed a different haplotype not found in Africa (++-++ ++-). These data are most consistent with an independent Asian origin of the sickle-cell mutation and provide further information about the geographic distribution of β(S)-haplotypes in the Old World. The distribution of the Asian β(S)-haplotype corresponds to the reported geographic distribution of a mild clinical phenotype of homozygous SS disease.