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In the last decade more states and countries are adopting newborn screening for salt-wasting CAH due to 21-hydroxylase deficiency, which leads to death in the first month of life if not recognized. [57] [23] The salt-wasting form of CAH has an incidence of 1 in 15,000 births and is potentially fatal within a month if untreated.
In all its forms, congenital adrenal hyperplasia due to 21-hydroxylase deficiency accounts for about 95% of diagnosed cases of CAH. [2] Unless another specific enzyme is mentioned, "CAH" in nearly all contexts refers to 21-hydroxylase deficiency. (The terms "salt-wasting CAH", and "simple virilizing CAH" usually refer to subtypes of this ...
The condition of 21-hydroxylase deficiency is screened by measuring serum levels of 17α-hydroxyprogesterone (17-OHP) in the morning and between day 3 and 5 of the menstrual cycle (for females) to reduce the possibility of false positive results. [11] 17-OHP is used as a marker of the 21-hydroxylase enzyme activity since the 1980s. [51]
Steroid 21-hydroxylase is a cytochrome P450 enzyme that is notable for its substrate specificity and relatively high catalytic efficiency. [48] Like other cytochrome P450 enzymes, steroid 21-hydroxylase participates in the cytochrome P450 catalytic cycle and engages in one-electron transfer with NADPH-P450 reductase. Steroid 21-hydroxylase is ...
Most infants born with lipoid CAH have had genitalia female enough that no disease was suspected at birth. Because the adrenal zona glomerulosa is undifferentiated and inactive before delivery, it is undamaged at birth and can make aldosterone for a while, so the eventual salt-wasting crisis develops more gradually and variably than with severe 21-hydroxylase-deficient CAH.
21-deoxycortisol is a marker of congenital adrenal hyperplasia due to 21-hydroxylase deficiency, [2] [1] [3] even in mild (non-classic) cases. [4] [5] It can be also used for newborn screening. [6] The deficiency of the 21-hydroxylase enzyme leads to excess of 17α-hydroxyprogesterone, [7] [8] a 21-carbon (C 21) steroid.
The mineralocorticoid aspect of severe 3β-HSD CAH is similar to those of 21-hydroxylase deficiency. Like other enzymes involved in early stages of both aldosterone and cortisol synthesis, the severe form of 3β-HSD deficiency can result in life-threatening salt-wasting in early infancy.
Classic CAH, the disorder targeted by newborn screening programs, is caused by a deficiency of the enzyme steroid 21-hydroxylase and comes in two forms – simple virilizing and a salt-wasting form. The incidence of CAH can vary greatly between populations.