Sympathetic Meta-Analysis of Adrenoceptor Gene Variants in Hypertension

The literature on the molecular genetics of essential hypertension contains a considerable array of divergent and inconsistent findings. Contributing factors are differences between study groups in diet and lifestyle, genetics, inclusion criteria, choice of control groups, and limited sample size. Add to this the rarely addressed, but obvious factor of depletion with age of alleles that predispose to increased mortality, which can invert an association with hypertension, in that the allele that increases risk will be lost by attrition from the gene pool as the hypertensive population gets older.1 A valuable way of smoothing over the bumps and wrinkles between a body of studies is to perform a meta-analysis. Obviously the more studies the more powerful and meaningful will be the outcome. Meta-analyses will, however, miss unpublished, usually negative, data. The sympathetic nervous system has an important role in blood pressure. Thus genes of the sympathetic nervous system are prime candidates for molecular genetic studies in hypertension. In the present issue, Kitsios and Zintzaras examined data from 163 genetic association studies and eight genome-wide association studies (GWAS).2 They report findings from an extensive meta-analysis of data on 37 polymorphisms in 7 adrenoceptor genes. Importantly, a number of these genetic variants affect receptor function or gene expression, so adding to the plausibility of causative role(s) in hypertension.