Haemoglobin genotypes: a prevalence study and implications for reproductive health in Uyo, Nigeria

Abstract

Background: Haemoglobinopathies are among the most common genetic disorders worldwide, inherited as autosomal recessive disorders from healthy-carrier parents. The most common are the sickle cell disorders and the thalassaemias, occurring in people of African, Asian, South European and Middle Eastern descent. The University of Uyo Teaching hospital (UUTH), Uyo, Akwa Ibom state, Nigeria is a tertiary health institution providing the health needs of the host and neighbouring states in South-south and South East Nigeria. There is currently paucity of data on the haemoglobin genotype distribution in Akwa Ibom state, hence the need for this study, considering its importance in medical diagnosis, patient management, genetic information and counselling. Methods: This is a retrospective study. Registers and results of all haemoglobin genotype investigations carried out in the department of Haematology, University of Uyo Teaching Hospital, Uyo between January, 2003 and December, 2007 were extracted, reviewed and analyzed using simple percentages. Results: Eight thousand and ninety seven Haemoglobin genotype tests carried out over a five year period were analysed: 6376 (78.7%) of these were HbAA, 1580 (19.6%) HbAS, 121 (1.5%) HbSS, while HbAC and SC accounted for 16 (0.2%) and (0.04%) respectively. The ratios of Hb AA to Hb AS, HbAAto HbSS andHbAAtoHbAC were 4:1, 52:1 and 400:1 respectively. Of the 8097 subjects, 6723(83.0%) were females, 1152(14.2%) were males. Among the females, 4.8% of HbSS and HbSc were in children under 15 years while only 0.3% were in those 15 – 44 years. Conclusion: While HbAA is the predominant genotype in our environment, there is also a significant number of the abnormal haemoglobin genes. Withmany children with sickle cell disease now surviving to adulthood due to advances in medicine, a larger number of women with sickle cell disease in pregnancy with all the attendant challenges it poses should be expected in our environment. It is necessary therefore, to keep abreast with developments in the area of its management in order to cope with the challenges.

Keywords: Haemoglobinopathy, Genotype, Sickle cell disease