Variations in Fat-mass and Obesity-associated (FTO) Genes and Allelic Distribution in Some Selected Ethnic Populations in Niger Delta, Nigeria

Aim: To evaluate variations in FTO genes and allelic distribution in some ethnic populations in Niger Delta, Nigeria.

Study Design: Case-controlled observational study.

Place and Duration of Study: Federal Medical Centre, Asaba, Delta State and Safety Molecular Pathology Laboratory, Enugu, Nigeria, between March 2020 and February 2022.

Methodology: The association between sixteen (16) Single Nucleotide Polymorphisms in the FTO gene and some biomarkers of obesity and type 2 diabetes subjects (78 cases and 20 controls) from four different tribes in the Niger Delta region, Nigeria. Multistage sampling method was employed in the subject selection. The subjects were first separated into two groups – new cases (less than a year of diagnosis as Diabetic) and old cases (one year & above). Equal number of samples was then randomly collected from each of the cluster groups. Ten millilitres of blood were collected into EDTA for genotyping using Illumina NextSeq 2000 sequencing platform. Hardy-Weinberg Equilibrium statistical test was used to determine the variation in distribution of the alleles and genotypes within the study population while allelic frequencies were calculated by gene counting. Chi-square (and fisher’s test where chi-square was not applicable) and Odd Ratio (OR) were performed to determine the significant differences and associated risks respectively of the allelic and genotypic frequencies of Type 2 diabetic (T2D) and non-diabetic subjects of the FTO gene variants.

Results: The results of Hardy-Weinberg Statistical Test, Genotype and Allelic Distribution of FTO gene Variants in Obese/T2D Subjects in Different Tribes of Niger Delta are presented in Tables(1-4) for rs73609956 (C>T), rs116753298 (T>C), rs201041270 (A>G), rs531215275 (A>C), rs146056278 (C>T), rs1410999299 (G>A), rs79206939 (A>G), rs145884431(G>A), rs61743972 (G>A), rs201496428 (C>T), rs146138389 (T>C), rs886052102 (A>G), rs144743617 (G>A), rs886052103 (T>A), rs9939609 (A>T) and rs8050136 (A>C). However, no significant differences in analyzed genotype frequencies were found between T2D and healthy controls.

Conclusion: Knowledge of the dominant SNPs in some ethnic groups, may provide platform to delay its expression through informed wise choice of lifestyle change and proper dieting.