Neuronal expression of ATP-binding cassette, sub-family B (MDR/TAP), member 1 (ABCB1) has been demonstrated after brain ischemia. To investigate whether ABCB1 polymorphisms are associated with the development, risk factors (hypertension, dyslipidemia, and diabetes mellitus), severity (National Institutes of Health Stroke Scale, NIHSS), and sequelae (Modified Barthel Index, MBI) of ischemic stroke (IS), four single nucleotide polymorphisms (SNPs) of the ABCB1 gene [rs4148727, promoter, -154T>C; rs3213619, 5'-untranslation region (5'UTR), -129T>C); rs1128503, synonymous, Gly412 (C>T); rs3842, 3'UTR, A>G] were analyzed in 121 IS patients and 291 control subjects. SNPStats and SPSS 18.0 were used to obtain odds ratios (OR), 95% confidence intervals (CI), and p values. Multiple logistic regression models (codominant1, codominant2, dominant, recessive, and log-additive models) were applied to analyze the genetic data. The rs3842 SNP was weakly associated with the development of IS (p=0.020 in codominant1 model and p=0.028 in dominant model). In the analysis of clinical phenotypes, ABCB1 polymorphisms were nominally associated with hypertension (rs3213619 and rs3842, p<0.05), dyslipidemia (rs1128503, p<0.05), diabetes (rs3842, p<0.05), and NIHSS (rs4148727, p<0.05). Interestingly, rs3842 showed statistically strong association between IS with hypertension and IS without hypertension (Fisher's exact p=0.003, OR=0.11, 95% CI=0.03-0.51 in recessive model). These results suggest that the ABCB1 gene may be associated with the development and clinical phenotypes of IS in Korean population.

Keywords: ABCB1, clinical phenotypes, MBI, NIHSS, ischemic stroke, single nucleotide polymorphism