Positive neonatal screening test for congenital adrenal hyperplasia in a case with 3β-hydroxysteroid dehydrogenase...

The neonatal CAH screening test is mainly performed for early detection of and avoidance of mortality due to salt-wasting crises related to severe 21-hydroxylase deficiency. 3β-hydroxysteroid dehydrogenase type 2 (HSD3B2) deficiency is a rare subtype of CAH that leads to salt-wasting crises. To present a case of HSD3B2 deficiency with a positive neonatal CAH screening test, emphasizing the role of newborn screening in early diagnosis.

A 46,XY newborn who assigned female at birth, was admitted on the fifth postnatal day due to atypical genitalia. His neonatal CAH screening test subsequently resulted positive. Low cortisol and aldosterone levels, elevated adrenocorticotropic hormone (ACTH), hyponatremia, and hyperkalemia were detected. Steroid hormone profile suggested a diagnosis of HSD3B2 deficiency, and subsequent genetic testing revealed compound heterozygous variants in the HSD3B2 gene. Electrolyte balance was achieved with hydrocortisone and fludrocortisone replacement therapy.

The neonatal CAH screening test offers an extra advantage in guiding early diagnosis and treatment of patients with rare salt-wasting forms of CAH, such as HSD3B2 deficiency in countries where these conditions are relatively more common.