Hormonal hypertension in children: 11 beta-hydroxylase deficiency and apparent mineralocorticoid excess

Blood pressure is determined by the product of cardiac output, intravascula r volume, and peripheral resistance. Because hormones are involved in blood pressure regulation and affect these parameters, hypertension is a promine nt feature of certain adrenal enzymatic abnormalities, In this report, two steroid-dependent forms of genetic low-renin hypertension are examined: 11 beta -hydroxylase deficiency and apparent mineralocorticoid excess. 11 beta -Hydroxylation is an enzymatic function necessary for the biosynthe sis of cortisol by the zona fasciculata (ZF) of the adrenal cortex, Defects in this step lead to the abnormally increased production by the ZF of the steroid Il-deoxycorticosterone (DOC), a moderately potent mineralocorticoid , which causes sodium retention and volume expansion that result in hyperte nsion. Further, the excess production of adrenal androgens leads to viriliz ation, prenatally in the genetic female, and postnatally in both sexes. The disorder of 11 beta -hydroxylase deficiency is due to an autosomal recessi ve defect of the enzyme protein-encoding gene CYP11B1, Numerous mutations i n CYP11B1 causing 11 beta -hydroxylase deficiency have been characterized. Apparent mineralocorticoid excess is a potentially fatal genetic disorder c ausing severe juvenile hypertension, pre- and postnatal growth failure, and low to undetectable levels of potassium, renin, and aldosterone, It is cau sed by autosomal recessive mutations in the HSD11B2 gene, which result in a deficiency of 11 beta -hydroxysteroid dehydrogenase type 2 (11 beta -HSD2) .