The results indicated that ischemic stroke had a significant association with the CYP1A1 genotype ‘CC’ (P=0.01; OR, 5.14; 95% CI, 1.14–23.14) in south Indian population, whereas Zhang et al (89) showed that CYP1A1 decreased the risk of disease in the eastern Han of China, and this contradiction showed CYP1A1 gene to display distinct alleles distribution among populations. The gene discussed is CYP1A1; the disease is ischemic stroke.