The haptoglobin promoter polymorphism rs5471 is the most definitive genetic determinant of serum haptoglobin level in a Ghanaian population

Abstract

BackgroundThe serum haptoglobin (HP) level varies in various clinical conditions and among individuals. Recently, the common HP alleles, rs5472, and rs2000999 have been reported to associate with serum HP level, but no studies have been done on Africans. Here, we explored the relationship of not only these polymorphisms but also rs5470 and rs5471 to the serum HP level in 121 Ghanaians. MethodsGenotyping of rs2000999 was performed by PCR using hydrolysis probes, while the other polymorphisms have been already genotyped. Serum HP level was measured by a sandwich ELISA. ResultsWe observed a significant association between rs5471 and the serum HP level (p = 0.026). It was also observed within the subgroups of HP2/HP2 and HP2/HP1. In addition, we detected a trend toward lower HP levels for individuals with the A allele of rs2000999 than those without A, but it was not statistically significant (p = 0.156). However, we did not observe the clear associations between other polymorphisms and serum HP level that were observed for Europeans and Asians because of the small sample size and the complexity of SNPs affecting the HP level. ConclusionsWe suggest that rs5471 is a strong genetic determinant of HP levels in Ghanaians, and this seems to be characteristic of Africans. Further investigation using large scale samples will help in understanding the genetic background of individual variability of the serum HP level.