Genotype-phenotype correlations of mutations and polymorphisms in HSD11B2, the gene encoding the kidney isozyme of 11β-hydroxysteroid dehydrogenase

Mutations in the HSD11B2 gene encoding the kidney (11-HSD2) isozyme of 11 beta -hydroxysteroid dehydrogenase cause the syndrome of apparent mineralocorticoid excess, a form of salt-sensitive hypertension. Enzymatic activities of mutant enzymes measured in cultured cells are correlated with several parameters of clinical severity including urinary steroid product:precursor ratios, age at diagnosis, birth weight and potassium levels, but not with blood pressure. In normals or in subjects with essential hypertension, sensitivity of blood pressure to salt loading is correlated with activity of renal 11-HSD2, as measured by an increase in the ratio of urinary free cortisol/urinary free cortisone UFF/UFE), and also correlated with length of a CA repeat polymorphism in the first intron of HSD 11B2. A functional explanation for these associations remains to be elucidated.