Interethnic differences in carriage of haemoglobin AS and Fcγ receptor IIa (CD32) genotypes in children living in eastern Sudan

Fulani and Masaleit, two sympatric ethnic groups in eastern Sudan, are characterized by marked differences in susceptibility to Plasmodium falciparum malaria. It has been suggested that sickle cell trait carriage may protect from the most severe forms of malaria. Previously, we have shown that Fc gamma RIIa polymorphism is associated with the outcome of malaria disease. The present study aimed at determining whether the two tribes differ in the frequency of Fc gamma RIla and Hb AS genotypes. For this, genotyping of Fc gamma RIIa and Hb AS in 70 Fulani and 70 Masaleit age- and sex-matched subjects was conducted. The frequency of Fc gamma RIIa H/H131 genotype was higher in the Fulani as compared to the Masaleit group (40.0% versus 14.3%; adjusted odd ratio [OR] = 3.05, 95% confidence interval [CI] = 1.19-7.82 and P = 0.02), while the R/R131 genotype was significantly higher in the Masaleit group (14.3% for Fulani versus 45.0% for Masaleit; adjusted OR = 0.26, 95% CI = 0.11-0.64 and P<0.01). With regard to Fc gamma RIIa allele frequencies, there were significant differences between the Fulani and Masaleit ethnic groups. Thus, the H131 allele was more frequent than the RI 31 among Fulani children (0.63 versus 0.37, OR = 3.23, 95% CI = 1.93-5.45 and P<0.001). The frequency of the Hb AS genotype was lower in the Fulani compared to the Masaleit group (15.7% versus 30.0%, respectively, adjusted OR = 0.02, CI = 0.01-0.18 and P<0.0 1). These data suggest that Fc gamma RIIa and Hb AS polymorphisms may contribute to the clinical outcome of malaria. We conclude that the H/H131 genotype and HI 31 allele rather than Hb AS genotype (sickle cell trait patients) appear to associate with the Fulani ethnic group. (C) 2007 Elsevier B.V. All rights reserved.