THE HEMATOLOGIC CHARACTERISTICS OF SICKLE-CELL-ANEMIA BEARING THE BANTU HAPLOTYPE - THE RELATIONSHIP BETWEEN G-GAMMA AND HBF LEVEL

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  • 1 April 1987
    • journal article
    • research article
    • Vol. 69  (4) , 1026-1030
Abstract
Previous work has demonstrated that the HbS gene has appeared and expanded three times in Africa in three separate geographic locations and that these three distinct mutational events can be identified by linked DNA polymorphic sites (haplotypes) surrounding the abnormal gene. We have reported that the Senegalese and Beninian haplotypes differ in G.gamma. expression, mean percentage of HbF, and percentage of dense cells. We now report on the third haplotype, the Bantu, and find that it has intermediate features, namely, the high mean percentage of HbF and low percentage of dense cells associated wtih the Senegalese haplotype, but with a low percentage of G.gamma. expression similar to the Beninian haplotype. The distribution of percent HbF is quite different from Senegal haplotype-bearing sickle cell anemia patients since it covers a much wider range. The low G.gamma. expression is also different from the Beninians since it contains a significant and unique cluster of individuals with lower than 38% G.gamma.. Interestingly, among the Bantu there is a strong correlation between HbF levels and G.gamma. expression, which is not seen with the other haplotypes. These findings open the possibility that among the Bantu haplotype-bearing individual two chromosomal types exist that define different levels of G.gamma. and HbF expression. Further structural exploration of these two potential subhaplotypes is needed.