Beckwith-Wiedemann Syndrome Presenting with Transient Features of Congenital Adrenal Hyperplasia in a Nigerian Neonate.

Presentation of Beckwith-Wiedemann syndrome (BWS) is widely variable. Congenital adrenal hyperplasia (CAH) is the leading cause of atypical genitalia in the female newborn. Beckwith-Wiedemann syndrome was previously not recognized as a possible cause of a false diagnosis of CAH. A late preterm (gestational age of 36 weeks) female presented at the 3rd hour of life with an anterior abdominal wall defect and swelling. Examination revealed coarse facial features, macroglossia, omphalocele major, prominent labia majora with hyperpigmented and enlarged clitoris. Weight was >97th percentile for age and sex, with length and occipitofrontal circumference at 95th and 50th percentiles, respectively. Initial blood investigations revealed hypoglycaemia, hyponatraemia, hypocortisolaemia, elevated testosterone and 17-hydroxyprogesterone with female internal genitalia suggesting CAH. She was commenced on hydrocortisone. Omphalocele was managed conservatively. Abdominal ultrasound scan showed no enlargement of the adrenal glands or tumours. Genetic analysis showed hypomethylation at KCNQ1OT1: TSS-DMR (IC2) within 11p15.5, confirming a diagnosis of BWS. Clitoromegaly resolved spontaneously at six months of life without any surgical intervention, with normal pigmentation of the external genitalia. Steroids were tapered off, and repeat adrenal metabolites are normal. BWS may present with transient features suggestive of CAH.