Variations in the β-globin genes of sickle cell anaemia patients in Zaria, Northwestern, Nigeria. Niger

Abstract

Context: Sickle Cell Anaemia (SCA) is a genetic disorder with a life-long disability, which is of public health importance. The diversity in its clinicopathologic and laboratory presentations may be due to the interplay between additional genetic differences and environmental factors. The genetic factors may be within the β-globin gene itself, the β-globin gene cluster or elsewhere in the genome.

Aim: To characterize the β-globin gene for variations associated with the Sickle Cell mutation.

Settings and Design: A cross-sectional descriptive study involving 51 adult SCA patients attending Sickle Cell Clinic of Haematology Department Ahmadu Bello University (ABUTH) Zaria, Kaduna State, Nigeria.

Methods and Material: The buccal swab specimens were collected and β-globin gene DNA sequencing was done. The sequences obtained were compared with a Genbank Reference β-globin gene (NC_000011.9) using Basic Local Alignment Search Tool (BLAST), and variations noted. Data generated were analyzed using SPSS Version 20.0. Statistical analysis used: Data generated was summarized by using charts, means±2SD, and 95% confidence intervals.

Results: There were 40 (78.43%) females and 11 (21.57%) males. The mean age of the participants was 25.35 ± 7.67 years, 95% CI (23.20, 27.51). The classic sickle cell mutation A T was present in all participants. The mean number of β-Globin gene variations was 8.61±11.30, 95% CI (5.43, 11.78). The number of Substitutions were 122 (27.79%), insertions 184 (41.91%), and deletions 133 (30.30%). These occurred in various combinations. The mean number of substitutions, insertions, and deletions were 2.39±3.23, 3.61±7.66, and 2.60±2.46 with 95% CIs of (1.48, 3.30), (1.45, 5.76), and (1.92, 3.30) respectively. Conclusions: There are β-globin gene variations in SCA patients in Zaria, and locally relevant genetic database of the SCA population will be the cornerstone in understanding genotype-phenotype interactions in this disorder.

Key Messages: There are β-globin gene variations in SCA patients in Zaria. Generating locally relevant genetic databases of the SCA population will be the cornerstone in understanding genotype-phenotypeinteractions in this condition.

Keywords: β-globin gene, sca, variations