Association between a-adducin gene polymorphism (Gly460Trp) and genetic predisposition to salt sensitivity: a meta-analysis

Linkage and association studies suggested the relationship between a-adducin polymorphism (Gly460Trp; rs4961) and genetic susceptibility to salt-sensitivity. However, the currently available results were inconsistent. This study aimed to define quantitatively the association between salt-sensitivity and α-adducin Gly460Trp polymorphism in all published case-control studies. Publications from PubMed and other databases were retrieved. The major inclusion criteria were: (1) case-control design; (2) salt-sensitivity confirmed by sodium loading tests, and (3) the distribution of genotypes given in detail. Seven case-control studies fulfilled the inclusion criteria. In total they involved 820 subjects (454 salt-sensitive and 366 non-salt-sensitive). The meta-analysis shows that Gly460Trp polymorphism in general is not significantly associated with salt-sensitivity OR (95%CI): 1.40 (0.96, 2.04),P = 0.08]. Subgroup analysis showed that the association is statistically significant in Asian people OR (95%CI):1.33 (1.06, 1.69),P = 0.02] but not in Caucasian people OR (95%CI):1.98 (0.57, 6.92),P = 0.28]. This indicates that blood pressure response to sodium varies between ethnical groups. More studies based on a larger population are required to evaluate further the role of a-adducin Gly460Trp polymorphism in salt-sensitive hypertension.