Association of PCSK9 and CCL22 gene polymorphisms with myocardial infarction in a South Indian population

Myocardial infarction (MI) remains a major global cause of morbidity and mortality, with a particularly high burden among individuals with type 2 diabetes mellitus (T2DM). Host genetic factors play a significant role in modulating individual susceptibility to MI by influencing lipid metabolism and immune-mediated inflammatory pathways. The proprotein convertase subtilisin/kexin type 9 (PCSK9) gene is a key regulator of cholesterol homeostasis, while C-C motif chemokine ligand 22 (CCL22) is involved in immune cell recruitment and vascular inflammation. In this study, we investigated the association of PCSK9 rs505151 and rs11591147 and CCL22 rs4359426 polymorphisms with MI risk in a South Indian population. This case-control study included 400 participants categorized into controls (n = 100), MI (n = 100), T2DM (n = 100), and MI with T2DM (n = 100). Significant differences in clinical and biochemical parameters, including lipid indices and cardiometabolic risk markers, were observed between groups (p < 0.05). Genetic analysis revealed a significant association between the PCSK9 rs505151 variant and MI susceptibility across allelic and genotypic distributions, with significant effects under dominant and recessive inheritance models. Multivariable logistic regression confirmed that the rs505151 risk genotype was independently associated with MI after adjustment for age, sex, body mass index, and smoking status. In contrast, PCSK9 rs11591147 was rare and showed no significant association. The CCL22 rs4359426 polymorphism showed limited evidence of association with MI, with a significant effect observed only under the dominant inheritance model. Furthermore, combined analysis using a genetic risk score suggested that cumulative genetic burden involving PCSK9 and CCL22 variants was associated with an increased risk of MI. Overall, our findings suggest that genetic variation in lipid-regulatory and immune-related pathways may contribute to MI susceptibility in South Indians. Further studies are warranted to validate these associations and clarify their biological and clinical relevance.