The results of many studies performed on animals and humans strongly suggest that genetic factors lead to the development of hypertension (HT). Syndromes in which mutations in single genes are sufficient to result in large changes of blood pressure are rare. Nevertheless, it is anticipated that their understanding will lead to new insights into forms of hypertension occurring more often, including essential hypertension. At least 9 monogenic forms of HT including Liddle syndrome, type I familial hyperaldosteronism (GRA) and type II familial hyperladosteronism, Gordon syndrome, apparent mineralocorticoid excess syndrome (AME), hypertension associated with type E brachydactyly, glucocorticoid receptor mutations, type IV congenital adrenal hyperplasia (CAH) (11 beta-hydroxylase deficiency), and type V CAH (17 alpha-hydroxylase deficiency) have been described so far.