Congenital Adrenal Hyperplasia with Non-functional Mutations in Both Alleles in a Clinically Unaffected Infant.

BACKGROUND Results in neonatal screening programs aiming at detection of congenital adrenal hyperplasia (CAH) can only report elevated levels of 17-hydroxy-progesterone (17-OHP), without being able to differentiate presence or absence of salt loss. AIM To predict presence or absence of salt loss in newborn infants with CAH. METHODS The first specimen of suspected CAH in samples sent from People's Democratic Republic of Laos (Lao PDR) was investigated for known mutations in CAH associated with salt loss. RESULTS Molecular genetic diagnosis revealed mutations associated with loss of function in both alleles; however, the infant was clinically unaffected even without any corticosteroid substitution therapy. CONCLUSIONS Although molecular genetic methods can theoretically predict loss of function in CAH, our infant was clinically unaffected even without therapy at 6 years of age. We speculate that in CAH, remaining enzyme activity can be sufficiently high, despite the presence of loss of function mutations, which do not affect infants clinically.