Genetics of hypertension. Current status.

Genetics of hypertension is complex with no known single gene playing a major role, but rather many genes each with mild effects reacting to different environmental stimuli contribute to blood pressure. The heritable component of blood pressure has been documented in familial and twin studies suggesting that 30%-50% of the variance of blood pressure readings are attributable to genetic heritability and about 50% to environmental factors. Early studies in hypertension identified specific enzymes, channels and receptors implicating sodium handling in the regulation of blood pressure including genes involved with the renin-angiotensin-aldosterone system controlling blood pressure and salt-water homeostasis, proteins in hormonal regulation of blood pressure (enzymes and receptors of the mineralo- and glucocorticoid pathways) and proteins coded by genes involved in the structure and/or regulation of vascular tone (endothelins and their receptors). The field of molecular genetics has revolutionized the study of hypertension by identifying single gene syndromes or Mendelian forms and several candidate genes for blood pressure variance. Genes have been localized to at least 20 chromosome regions. For example, recent genome-wide association studies (GWAS) of common genetic variants found 13 single nucleotide polymorphisms (SNPs) or variants in systolic and 20 for diastolic blood pressure readings representing different genes and genetic heterogeneity. Further understanding of the genetics of hypertension will require the use of advances in bioinformatics tools and genetic technology [e.g., SNP, exon and noncoding (micro) RNA arrays]. New approaches will allow for identification of not only single genes, but other interacting genes contributing to hypertension by merging multiple genetic data sets (structural and functional) from individuals with hypertension and development of new molecular targets for study and treatment.