Racial differences and the genetics of hypertension.

Variation in the prevalence of hypertension among human populations has been used to examine a wide range of research questions. The best known example has always been the twofold greater prevalence among blacks, which has provoked a debate about the relative importance of environmental and genetic factors. This problem is complicated because it requires an understanding of both the genetics of hypertension and the genetic basis of variation among populations. Molecular data accumulated over the past year are beginning to provide new insights into this old question. Modest progress has now been made in the genetics of hypertension. Important advances have been made in understanding rare hypertension syndromes, and large-scale studies of the general population are under way, although the results to date are inconclusive. Markers used to search for hypertension genes can also provide estimates of between-population variability. These data, which are based on genetic variants used for etiologic research, confirm previous evidence of group-specific variation, while underscoring the limited magnitude of this variation. Despite rapid progress, this work is still in its infancy and raises more questions than it answers.