Congenital Adrenal Hyperplasia: A Detailed Review of 21-Hydroxylase Deficiency

The document from 2008 provides a detailed review of congenital adrenal hyperplasia (CAH), particularly the most common form, 21-hydroxylase deficiency. It explains that CAH is an autosomal recessive disorder that leads to impaired cortisol biosynthesis and excessive adrenal androgen synthesis due to mutations in genes encoding steroidogenic enzymes. The incidence of 21-hydroxylase deficiency is between 1 in 5,000 to 1 in 15,000, with a carrier frequency of 1 in 60, varying by ethnicity and race. Clinical features include ambiguous genitalia in females, salt-wasting in about 75% of classic cases, and premature pubarche. The document also discusses the importance of newborn screening, the use of hormone replacement therapy to manage the condition, and the psychosocial and fertility issues faced by individuals with CAH. Additionally, it covers the differentiation of nonclassical CAH from polycystic ovary syndrome (PCOS), emphasizing the need for accurate diagnosis through ACTH stimulation tests and the different treatment approaches for CAH and PCOS.