Defects in cortisol metabolism causing low-renin hypertension

Deficiency of steroid 11βhydroxylase, which is a mitochondrial cytochrome P450 required for cortisol and aldosterone synthesis, causes hypertension as well as virilization. In addition, abnormal regulation of this enzyme or a closely related isozyme may be involved in an autosomal dominant form of inherited hypertension, dexamethasone-suppressible hyperaldosteronism. An enzyme that catalyzes the interconversion of cortisol and cortisone, 11βhydroxysteroid dehydrogenase, may be defective in an autosomal recessive form of hypertension termed apparent mineralocorticoid excess. The molecular bases of these forms of hypertension will be elucidated by identifying mutations in the 11βhydroxylase and 11βhydroxysteroid dehydrogenase genes and expressing normal and mutagenized enzymes in cultured cells.