A novel homozygous CYP17A1 mutation causes partial 17 α-hydroxylase/17,20-lyase deficiency in 46,XX: a case report and literature review.

What is the context?17-OHD is a rare cause of secondary hypertension, often with hypokalaemia, primary amenorrhoea and absence of secondary sex characteristics.Partial 17-OHD is an even rarer subtype of 17-OHD, with subtler symptoms.There are few reports concerning partial 17-OHD, especially in 46,XX patients.What is new?We reported a case of a 46,XX patient with partial 17-OHD caused by a novel missense CYP17A1 mutation, c.391 A > C (p.T131P).We also conducted a literature review to summarise the clinical, hormonal and genetic characteristics of fourteen 46,XX probands with partial 17-OHD.From the literature review, we found that:Most 46,XX patients with partial 17-OHD presented with partial pubic hair, breast development, oligomenorrhea or secondary amenorrhoea, normotension, and/or normokalemia.All 46,XX patients with partial 17-OHD presented with elevated serum progesterone.However, the relationship between in vitro enzyme activities of the 17-hydroxylase and/or17,20-lyase and clinical severity is still unclear.What is the impact?The current study can help early detection and diagnosis of partial 17-OHD.