The Arg72 variant of the p53 functional polymorphism (rs1042522) is associated with coronary artery disease in young South Africans of Indian ancestry.

Background And Aim: Tumor protein p53 (p53), classically referred to as a tumor suppressor gene, is involved in cell cycle regulation and may be related to atherosclerosis by affecting smooth muscle cell proliferation, a feature of atherogenesis. A polymorphism at codon 72 (rs1042522) results in functional variability and hence plays a role in the pathophysiology of coronary artery disease (CAD). This polymorphism has been well established for its role in cancer and has only recently been investigated in CAD. Limited data is available on South Africans (SA) of Indian ancestry. We examined associations of this polymorphism and clinical markers in a cohort of young SA Indian CAD patients.

Methods: A total of 284 subjects were recruited into this study which included 100 CAD patients (diagnosed on angiography, mean age 37.5, range 24-45years), 100 age- and sex-matched Indian controls and 84 age- and sex-matched Black controls. Polymorphic variants were assessed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Data for clinical markers were obtained from pathology reports.

Results: Genotype distribution differed significantly between CAD patients and Indian controls (Pro/Pro, Pro/Arg, Arg/Arg: 24%, 48%, 28% vs. 30%, 61%, 9% respectively, p=0.0025). There was a significant genotype distribution between Indian and Black controls (Pro/Pro, Pro/Arg, Arg/Arg: 30%, 61%, 9% vs. 45.2% 40.5%, 14.3% respectively, p=0.0212). A significantly higher frequency of the p53 Arg72 allele was found in CAD patients compared to controls (52% vs. 39.5% respectively, p=0.0159). The variant allele was slightly higher in Indian controls (39.5%) compared to Black controls (34.5%), but this did not reach statistical significance (p=0.3324). The levels of total cholesterol, LDL, HDL, triglycerides, fasting glucose, fasting insulin and %HbA1c were not significantly influenced by the p53 genotypic variants.

Conclusion: Although the p53 codon 72 SNP is not associated with clinical markers of disease in CAD, the higher frequency of the variant allele in SA Indians may be a contributing factor for this population having an increased risk of developing premature CAD.