Haemoglobin haplotypes and probable allelic frequencies of natives of Okolobiri Community, Nigeria: Population genetics study

Abstract

Introduction: Sickle cell disease is an autosomal recessive disorder in which patients inherit one mutated copy of the β-globin gene from each parent. This inheritance results to sickle-shaped red blood cell and associated fragility which results in the destruction of the patients red blood cells. This project was carried out as a population genetic study to determine the frequencies of the haemoglobin haplotypes (A and S) and allelic frequencies with a view to predicting the dynamics of the abnormal genes using a typical African community as a case study.

Materials and Methods: Two hundred and twenty-eight (228) subjects constituted the study population of which one hundred and sixty four (164) were males (28%). Haemoglobin electrophoresis membrane at a pH 8.6 was used to establish the haemoglobin electrophoretic pattern of the study population.

Results: The haemoglobin electrophoretic pattern of the study participants were as follows: Hb AA (60.5%), Hb AS (25.5%) and HbSS (14%). The distribution among males were; HbAA (62.2%), HbAS (29.3%) and HbSS (8.5%). and females: Hb AA (56.3%), HbAS (15 .6%), HbSS (28.1%). The HbA haplotype frequency was 0.732 while the HbS was 0.268. the allelic frequencies obtained by Hardy-Weinberg calculation were as follows. HbAA (0.536), HbAS (0.392) and Hb SS (0.072). The χ² value of 29.475 obtained in this study was higher than the 3.84 at 5% significant level, hence, the null hypothesis that the population is not in Hardy-Weinberg equilibrium was accepted.

Conclusion: The study revealed high homozygous HbSS inheritance among females (28.1%) meaning that females are more affected than the males. The frequency of HbAS is expected to increase as this population is not in Hardy-Weinberg equilibrium. More awareness and sensitization is needed in our communities in order to reduce the prevalence of sickle cell anaemia in our African society.