Elevated G gamma gene expression with specific beta S gene haplotype, normal gamma gene maps and presence of the Xmn I site -158 5' to the G gamma gene in Indian sickle cell anemia.

In nine Indian patients ranging in age between four and 61 years, with mild Hb SS disease and very high Hb F levels, the G gamma globin chain levels of their fetal hemoglobin ranged between 64.0% and 70.0%, with a mean of 68.1% (S.D. +/- 2.6) of the total amount of gamma-globin chains. Eight of the nine patients were homozygous for a specific beta S gene haplotype #31. The other one was doubly heterozygous for the same specific haplotype and another haplotype, which differed from haplotype #31 by the presence of Bam HI site 3' to the beta gene and absence of Pvu II site 5' to the psi beta gene. The gamma gene organization studied by Pst I restriction enzyme analysis was found to be normal and the Xmn I site -158 5' to G gamma gene was present in all patients examined.