A pilot genome-wide association study of ischemic heart disease with co-occurring arterial hypertension in a Kazakh cohort

Genome-wide association studies (GWAS) of ischemic heart disease (IHD) remain underrepresented in Central Asian populations. We conducted a pilot GWAS of IHD with co-occurring arterial hypertension in a Kazakh cohort to identify candidate loci for future replication. A case-control GWAS was performed in 451 individuals (236 cases and 215 controls). Genotyping was conducted using the Illumina Infinium Global Screening Array-24 v3.0. Association testing was performed using a logistic regression under an additive genetic model adjusted for age, sex and the first ten principal components (PC1 - PC10). Multiple testing correction was applied using the Bonferroni adjustment. As an additional analysis, knowledge-guided GWAS (KGWAS) followed by MAGMA gene-based testing was used to prioritize candidate genes. After quality control, 345 371 variants were tested. Two loci surpassed the Bonferroni-corrected genome-wide significance threshold: rs28898595 at the UGT1A locus (effect allele C; OR = 0.33, 95% CI = 0.23 - 0.49; p = 3.01x10-8) and rs28709059 in the intron region of the ACTR3C gene (effect allele C; OR = 0.4, 95% CI = 0.29 - 0.55; p = 4.08x10-8). Several additional loci showed suggestive evidence of association. In gene-level analysis, the CSMD1 gene demonstrated a significant association signal in MAGMA consistent with the European (p = 1.16x10-11) and East Asian (p = 9.07x10-11) LD reference panels. This pilot study identifies genome-wide significant loci (UGT1A, ACTR3C genes) and supports CSMD1 gene as a prioritized candidate gene for the complex phenotype of IHD associated with co-occurring arterial hypertension in the Kazakh cohort. These findings are preliminary and require replication in larger Central Asian cohorts and further functional validation.