Association of rs4977574 with Lipid Phenotypes, Smoking Status, and Statin Exposure in a Saudi Cardiovascular Cohort:...

Background: Coronary artery disease (CAD) arises from the convergence of genetic susceptibility, lipid dysregulation, and modifiable environmental exposures. The polymorphism rs4977574, located proximal to the CDKN2A/CDKN2B gene cluster, has been repeatedly implicated in CAD risk across several populations, yet its relationship to intermediate cardiometabolic phenotypes and pharmacological treatment patterns in Saudi individuals remains poorly characterized. Objective: This study aimed to evaluate the association of rs4977574 with CAD status, lipid-related phenotypes, smoking history, obesity, and atorvastatin exposure in a Saudi cardiovascular cohort, and to assess the robustness of observed associations through sensitivity-adjusted analyses excluding participants with major metabolic confounders. Methods: A case-control genetic association study was conducted in Saudi participants with clinically confirmed CAD and healthy controls. Genomic DNA was genotyped for rs4977574 using TaqMan^® allelic discrimination assays. Genotype-phenotype associations were examined using chi-square testing, binary logistic regression under additive and dominant inheritance models, and one-way ANOVA for continuous lipid traits. Hardy-Weinberg equilibrium (HWE) was assessed in controls. Sensitivity analyses were conducted by sequentially excluding participants with obesity, smoking, diabetes mellitus, hypertension, dyslipidaemia, and statin use. Results: After covariate adjustment, rs4977574 was not independently associated with CAD case-control status under any inheritance model. Genotype-stratified analyses identified significant differences in HDL-cholesterol and triglyceride concentrations among cases, with no equivalent effects on total cholesterol or LDL-cholesterol. A significant association was observed between rs4977574 genotype and atorvastatin prescribing patterns. Sensitivity-adjusted analyses were directionally consistent with primary findings. HWE deviation persisted in controls after sequential metabolic exclusions, implicating population stratification or regional genetic heterogeneity rather than sample selection bias. Conclusions: Although rs4977574 did not associate independently with CAD susceptibility, its relationship with HDL-cholesterol, triglycerides, and atorvastatin exposure indicates that this locus contributes to cardiometabolic phenotypic heterogeneity in this Saudi cohort. These findings support phenotype-oriented and pharmacogenetically informed approaches in regional cardiovascular genetics and highlight the need for larger, ancestry-stratified investigations across Middle Eastern populations.