Delayed puberty from partial 17-alpha hydroxylase enzyme deficiency.

An 18-year-old woman with primary amenorrhoea and pubertal delay was investigated for mild labile hypertension and secondary hypogonadism. Low renin and normal aldosterone levels combined with evidence of primary adrenal insufficiency suggested partial 17-alpha hydroxylase enzyme deficiency. The diagnosis was confirmed by measurement of 24-hour urine steroid metabolites and whole gene sequencing of CYP17A1 that demonstrated c.160_162delTTC (p.Phe54del) homozygous mutation. Ultrasound showed bilateral small ovaries with multiple cysts. The serum anti-mullerian hormone concentration was unremarkable at 6.6 (normal <12.6 ng/ml) but the outlook for her future ovulatory potential is uncertain. Dexamethasone 0.25 mg pre-bed and hydrocortisone 5 mg on waking normalised her hormonal profile and her blood pressure without side-effects.