Association of APOE Gene Polymorphism with Stroke Patients from Rural Eastern India

CONTEXT: Studies from the different ethnic regions of the world have reported variable results on association of APOE gene polymorphism in stroke. AIM: The aim of this study is to find out the possible association of APOE polymorphism in stroke patients in ethnic Bengali population. SETTINGS AND DESIGN: A prospective case–control study was undertaken in the Department of Neurology, Burdwan Medical College, Burdwan, West Bengal, India, over a period of 3 years. METHODS: We collected 10 ml venous blood samples from 148 clinically and radiologically diagnosed acute stroke patients (80 of ischemic stroke and 68 of intracerebral hemorrhage) and consecutive 108 ethnic age- and sex-matched controls, in ethylenediaminetetraacetic acid vials after informed written consent. Genomic DNA was prepared at S.N. Pradhan Centre of Neurosciences, University of Calcutta, Kolkata, India. Exotic single-nucleotide polymorphisms (rs429358, rs 7412) were analyzed by polymerase chain reaction-restriction fragment length polymorphism for genotype of APOE. RESULTS: The frequencies of different APOE allele among 80 ischemic stroke patients were 5.6% (n = 9) for E2, 75.68% (n = 121) for E3, and 18.7% (n = 30) for E4. The E3 allele is significantly over-represented (P = 0.004) in controls compared to the patients (88% in controls vs 75.6% ischemic stroke patients and 80% hemorrhagic patients). A significantly high frequency of APOE4 allele was observed in ischemic (18.7%) and hemorrhagic patients (11%) compared to controls (8%). The E4 allele plays a major risk for developing ischemic stroke [odds ratio (OR) = 2.744; 95% confidence interval (CI): 1.43–5.10] and E3 plays a protective role for hemorrhagic stroke (OR = 0.53; 95% CI: 0.29–0.96), while E4 allele plays a nonsignificant (P = 0.31) increase in trend in hemorrhage stroke (OR = 1.4). CONCLUSIONS: There is significant association of APOE gene polymorphism in stroke patients of ethnic Bengali population. The E4 allele increases significant risk for development of ischemic strokes, and it also plays nonsignificant increase in trend in hemorrhagic strokes.