pediatrics
Congenital Adrenal Hyperplasia Caused by 21 Hydroxylase Deficiency
Diagnosis
Blood tests Possibly ACTH stimulation test Possibly genotyping Routine newborn screening typically includes measuring serum levels of 17-hydroxyprogesterone. If levels are elevated, the diagnosis of 21-hydroxylase deficiency is confirmed by identifying low blood levels of cortisol and by identifying high blood levels of DHEA, androstenedione, andtestosterone. Rarely, the diagnosis is uncertain, and levels of these hormones must be measured before and 60 minutes after ACTH is given (ACTH orcosyntropinstimulation test). Genetic testing can be done if results are inconclusive. In patients who develop symptoms later, ACTH stimulation testing may help, but genotyping may be required. Children with the salt-wasting form have hyponatremia and hyperkalemia; low levels of deoxycorticosterone, corticosterone, and aldosterone; and high levels of renin. Prenatal screeningand diagnosis (and experimental treatment) are possible;CYP21genes are analyzed if risk is high (eg, the fetus has an affected sibling with the genetic defect). Carrier status (heterozygosity) can be determined in children and adults. 