Increased first‐trimester nuchal translucency as a prenatal manifestation of salt‐wasting congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder that results from a deficiency in one or other of the five enzymes of cortisol biosynthesis. The most common form of CAH is 21-hydroxylase deficiency (21-OHD) and this may be manifest clinically in the neonatal period as a life threatening salt-wasting condition along side genital ambiguity. Prenatal diagnosis is available for CAH, however, there is poor correlation between the specific genotype and the phenotypic expression of the condition. We report two cases of severe salt-wasting CAH in one family that presented in both pregnancies with increased nuchal translucency (NT) in the first trimester. This is the first report of the association, between increased NT and CAH 21-OHD.