Prevalence of Congenital Adrenal Hyperplasia Due to 21-Hydroxylase Deficiency
Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency occurs in approximately 1 in 10,000 to 1 in 15,000 live births worldwide for the classical form, making it one of the most common autosomal recessive disorders. 1, 2, 3, 4, 5
Classical CAH Prevalence
- The classical form of 21-hydroxylase deficiency CAH affects approximately 1:10,000–1:15,000 live births in North America and Europe 6, 2, 3, 4, 5
- Among classical CAH cases, the salt-wasting form accounts for approximately 66–75% of patients, while the remaining 25–34% have the simple virilizing (non-salt-wasting) form 2, 3, 4, 5
- CAH is the most common cause of primary adrenal insufficiency in children, accounting for approximately 70% of pediatric cases 1
Non-Classical CAH Prevalence
- The non-classical (late-onset) form is substantially more common, occurring in approximately 0.2% to 3% of the general white population (1:100 to 1:500 individuals) 6, 3, 4, 5
- Non-classical CAH is often misdiagnosed as polycystic ovary syndrome in young women or idiopathic precocious pubarche in children 6, 3, 4, 5
Clinical Context and Importance
- CAH due to 21-hydroxylase deficiency is the most common cause of genital ambiguity in newborns 3
- The salt-wasting form carries significant mortality risk if undiagnosed, with adrenal crisis mortality occurring at approximately 0.5 per 100 patient-years 1, 7
- Newborn screening programs identify affected children before life-threatening salt-wasting crises develop, substantially reducing mortality 5
Geographic and Ethnic Variations
While the provided evidence focuses primarily on North American and European populations with the 1:10,000–1:15,000 prevalence, certain ethnic groups show higher carrier frequencies for non-classical CAH, particularly among Ashkenazi Jewish, Hispanic, and Slavic populations 6, 5.