Browsing by Subject "Gene Frequency"
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- ItemOpen AccessAPOL1 genetic variants, chronic kidney diseases and hypertension in mixed ancestry South Africans(2015) Matsha, Tandi E; Pheiffer, Carmen; Masconi, Katya L; Yako, Yandiswa Y; Erasmus, Rajiv TBackgroundThe frequencies of apolipoprotein L1 (APOL1) variants and their associations with chronic kidney disease (CKD) vary substantially in populations from Africa. Moreover, available studies have used very small sample sizes to provide reliable estimates of the frequencies of these variants in the general population. We determined the frequency of the two APOL1 risk alleles (G1 and G2) and investigated their association with renal traits in a relatively large sample of mixed-ancestry South Africans. APOL1 risk variants (G1: rs60910145 and rs73885319; G2: rs71785313) were genotyped in 859 African mixed ancestry individuals using allele-specific TaqMan technology. Glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations.ResultsThe frequencies of rs73885319, rs60910145 and rs71785313 risk alleles were respectively, 3.6%, 3.4%, and 5.8%, resulting in a 1.01% frequency of the APOL1 two-risk allele (G1:G1 or G1:G2 or G2:G2). The presence of the two-risk allele increased serum creatinine with a corresponding reduction in eGFR (either MDRD or CKD-EPI based). In dominant and log-additive genetic models, significant associations were found between rs71785313 and systolic blood pressure (both p ≤ 0.025), with a significant statistical interaction by diabetes status, p = 0.022, reflecting a negative non-significant effect in nondiabetics and a positive effect in diabetics.ConclusionsAlthough the APOL1 variants are not common in the mixed ancestry population of South Africa, the study does provide an indication that APOL1 variants may play a role in conferring an increased risk for renal and cardiovascular risk in this population.
- ItemOpen AccessErratum to: Investigation of the association between the TCF7L2 rs7903146 (C/T) gene polymorphism and obesity in a Cameroonian population: a pilot study(2017) Nguimmo-Metsadjio, Aurelie; Atogho-Tiedeu, Barbara; Noubiap, Jean Jacques; Evehe, Marie-Solange; Djokam-Dadjeu, Rosine; Donfack, Olivier Sontsa; Nanfa, Dieudonne; Mato, Edith Pascale M; Ngwa, Elvis Ndonwi; Guewo-Fokeng, Magellan; Pokam-Fosso, Priscille; Mbacham, Wilfred F; Mbanya, Jean Claude; Sobngwi, EugèneOBJECTIVE: This study aimed at investigating the association between the rs7903146 (C/T) polymorphism of the TCF7L2 gene with obesity in a Cameroonian population. METHOD: This was a case-control pilot study including 61 obese and 61 non-obese Cameroonian adults. Anthropometric indices of obesity, blood pressure, fasting blood glucose, and blood lipids were measured. The rs7903146 (C/T) polymorphism of the TCF7L2 gene was genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and genotypes were correlated with clinical and biological parameters. RESULTS: The T allele was predominant in the study population with a frequency of 93%. No statistically significant difference was however observed between the genotypic (p = 0.50) and allelic frequencies (p = 0.58) of obese and non-obese subjects. Comparison of clinical and biochemical parameters of C allele carriers (CX = CC + CT) with those of TT genotype showed that there was no significant difference between the lipid profile of these two groups. CONCLUSION: The rs7903146 (C/T) polymorphism of the TCF7L2 gene might not be associated with obesity in the Cameroonian population.
- ItemOpen AccessFat Mass and Obesity-Associated (FTO) Gene Polymorphisms Are Associated with Physical Activity, Food Intake, Eating Behaviors, Psychological Health, and Modeled Change in Body Mass Index in Overweight/Obese Caucasian Adults(2014) Harbron, Janetta; van der Merwe, Lize; Zaahl, Monique; Kotze, Maritha; Senekal, MarjanneThe fat mass and obesity-associated (FTO) gene is currently recognized as the most robust predictor of polygenic obesity. We investigated associations between the FTO rs1421085 and rs17817449 polymorphisms and the FTO rs1421085–rs17817449 haplotype and dietary intake, eating behavior, physical activity, and psychological health, as well as the effect of these associations on BMI. N = 133 treatment seeking overweight/obese Caucasian adults participated in this study. Genotyping was performed from whole blood samples. Weight and height was measured and a non-quantified food frequency questionnaire was completed to assess food group intake. Validated questionnaires were completed to assess physical activity (Baecke questionnaire), psychological health (General Health questionnaire, Rosenburg self-esteem scale and Beck Depression Inventory), and eating behavior (Three Factor Eating questionnaire). The risk alleles of the FTO polymorphisms were associated with poorer eating behaviors (higher hunger, internal locus for hunger, and emotional disinhibition scores), a higher intake of high fat foods and refined starches and more depressive symptoms. The modeled results indicate that interactions between the FTO polymorphisms or haplotypes and eating behavior, psychological health, and physical activity levels may be associated with BMI. The clinical significance of these results for implementation as part of weight management interventions needs further investigation.
- ItemOpen AccessParaoxonase1 Genetic Polymorphisms in a Mixed Ancestry African Population(2014) Macharia, M; Kengne, A P; Blackhurst, D M; Erasmus, R T; Matsha, T EParaoxonase 1 (PON1) activity is markedly influenced by coding polymorphisms, Q/R at position 192 and M/L at position 55 of the PON1 gene. We investigated the frequencies of these polymorphisms and their effects on PON1 and antioxidant activities in 844 South African mixed ancestry individuals. Genotyping was done using allele-specific TaqMan technology, PON1 activities were measured using paraoxon and phenylacetate, oxidative status was determined by measuring the antioxidant activities of ferric reducing antioxidant power and trolox equivalent antioxidant capacity, and lipid peroxidation markers included malondialdehyde and oxidized LDL. The frequencies of Q192R and L55M were 47.6% and 28.8%, respectively, and the most common corresponding alleles were 192R (60.4%) and 55M (82.6%). The Q192 was significantly associated with 5.8 units’ increase in PON1 concentration and 15.4 units’ decrease in PONase activity after adjustment for age, sex, BMI, and diabetes, with suggestion of differential effects by diabetes status. The PON1 L55 variant was associated with none of the measured indices. In conclusion, we have shown that the Q192R polymorphism is a determinant of both PON1 concentration and activity and this association appeared to be enhanced in subjects with diabetes.