Background: 17alpha-Hydroxylase deficiency (17OHD) is a rare disease of congenital adrenal hyperplasia. It is characterised by hypertension, hypokalaemia, primary amenorrhoea. Deficiency of P450c17 enzyme is caused by mutation of the CYP17 gene.
Case: A 16-year-old female with genotypic 46, XY suffered from 17OHD. She presented with primary amenorrhoea, lack of secondary sexual characteristics, and hypertension. Laboratory tests showed hypokalaemia, low levels of androgens (testosterone and dehydroepiandrosterone), corticosteroid, and high levels of adrenocorticotropic hormone and progesterone. A P409R mutation was found in exon7 of CYP17 gene, revealing homozygosis and confirming diagnosis of 17OHD.
Conclusion: 17OHD is a rare disease associated with primary amenorrhoea and hypertension. Identification of mutation in CYP17 gene can help to a better understanding of this enzyme deficiency.