Congenital adrenal hyperplasia due to 21-hydroxylase deficiency in South Africa.

BACKGROUND Congenital adrenal hyperplasia (CAH) caused by deficiency of the 21-hydoxylase (21-OH) enzyme is the most common form of CAH worldwide. OBJECTIVE To evaluate the prevalence of CAH due to 21-OH deficiency, and its clinical presentation and biochemical profiles in affected children. METHODS We performed a retrospective subset analysis of 44 children with confirmed CAH. RESULTS All the children had classic CAH. The majority (59.8%) had classic salt-wasting (CSW) CAH and 40.1% had simple virilising (SV) CAH. The median age of presentation was 8.1 years (interquartile range (IQR) 4.5 - 11) in the SV group and 2 months (IQR 2 weeks - 5 months) in the CSW group (p=0.0001). No difference in age of presentation was noted between males and females (p=0.541). The clinical presentation was significantly different between the CSW and SV groups, and between males and females in the CSW group (p<0.0001). Most of the females with 46,XX CSW CAH (66.7%) presented with disorders of sex development (DSD), while the remaining 33.3% presented with DSD and dehydration and shock. All the males with 46,XY CSW CAH presented with dehydration and shock. Overall, 37.9% (11/29) of the children were obese or overweight at presentation. Gonadotrophin-releasing hormone-dependent central precocious puberty was observed on follow-up in 29.4% (10/34) of the children at a median of 6.7 years (IQR 5 - 7.7). CONCLUSION The diagnosis of CAH is delayed in males and females in both SV and CSW forms of the disorder, which probably contributes to under-reporting of cases and a high mortality rate.