A rare combination: congenital adrenal hyperplasia due to 21 hydroxylase deficiency and Turner syndrome

A combination of Turner syndrome (TS) and classical congenital adrenal hyperplasia (CAH) is rare. A one-day-old newborn was referred to our hospital with ambiguous genitalia. The parents were third-degree relatives. The infant's weight was 3350g (50-75p), and the head circumference was 34.5cm (50p). The gonads were nonpalpable. Presence of a 3 cm phallus, one urogenital opening into the perineum, and incomplete labial fusion were identified. Laboratory tests revealed a classical type of CAH due to 21-hydroxylase deficiency. Karyotyping revealed a 45X0(35)/46XX(22) pattern with negative sex-determining region Y (SRY) on gene analysis. At the most recent follow-up visit, the patient appeared to be in good health - her height was 70.4 cm [-1.5 standard deviation (SD)] and her weight was 9.8 kg (0.3 SD). She was receiving hydrocortisone in a dose of 10 mg/m²/day, fludrocortisone acetate in a dose of 0.075 mg/day, and oral salt of 1 g/day. System examinations were normal. The patient's electrolyte levels were found to be normal and she was in good metabolic control. The findings of this patient demonstrate that routine karyotyping during investigation of patients with sexual differentiation disorders can reveal TS. Additionally, signs of virilism should always be investigated at diagnosis or during physical examinations for follow-up of TS cases. SRY analysis should be performed primarily when signs of virilism are observed. CAH should also be considered in patients with negative SRY.