Endocrine Abstracts

Introduction: Partial 21-hydroxylase deficiency is a genetic autosomal recessive disorder responsible for accumulation of the precursor upstream of the enzyme block, 17-hydroxyprogesterone (17OHP), and excessive androgen production.

Observation: A 29-year-old woman consulted for hirsutism with a Ferriman–Gallwey score of 25. There were no signs of Cushing syndrome and no abnormalities of sexual development. The Laboratory results revealed testosterone level of 0.76 ng/ml with elevated Δ4 androstenedione to 4.5 ng/ml. Cortisol level was comfortable at 180 ng/ml and 17OHP was elevated to 6 ng/ml and then to 14.6 ng/ml after Synacthen test confirming 21-hydroxylase deficiency. Pelvic ultrasound and adrenal CT scanning were normal.

Discussion: Partial 21-hydroxylase deficiency is responsible for more than 95% of late-onset congenital adrenal hyperplasia. It is distinct from the early so-called "classic" form due to a complete or major block and which results in virilization of a female child and/or syndrome of salt depletion. It usually reveals itself at puberty, sometimes years later. The most frequent reason for consultation is hirsutism, and justifies a Synacthen test with 17OHP in all cases of hirsutism with biological hyperandrogenism. The diagnosis is based on a 17OHP level above 10 ng/ml after stimulation. Management should include a molecular study of the CYP21B gene and a family investigation should be proposed.