Association between common genetic variants of α2A-, α2B-, and α2C-adrenergic receptors and ischemic stroke

Background: The alpha2-adrenergic receptor (α2-AR) mediates physiological responses to endogenous catecholamine, and genetic variants of α2-AR may predispose to clinical vascular diseases. We evaluated whether common genetic variants of each three subtype of alpha2-adrenergic receptor (ADRA2A, ADRA2B, and ADRA2C) were associated with ischemic stroke. Methods: A total of 616 patients with ischemic stroke and 512 controls were genotyped for the ADRA2A 1780G>A, ADRA2B 301-303 I/D, and ADRA2C 322-325 I/D polymorphisms. Logistic regression analyses, adjusting for multiple comparisons, were used to determine the association between the minor allele of each of three ADRA2 genes and the risk of ischemic stroke and pathophysiological subtypes. Results: The ADRA2B 301-303 D allele was more prevalent in the stroke group, compared to controls (DD vs. II, OR: 1.78, 95% CI: 1.18-2.69; recessive, OR: 1.55, 95% CI: 1.06-2.26). A subgroup analysis revealed that this association was found only in the small vessel diseases (SVD) type (DD vs. II, OR: 1.92, 95% CI: 1.11-3.33). The ADRA2A and ADRA2C polymorphisms did not contribute to an increased risk of ischemic stroke or any pathophysiological subtype. Conclusions: The ADRA2B 301-303 D allele confers an increased risk of overall ischemic stroke and SVD subtype.