Combined 17α-hydroxylase/17,20-lyase deficiency due to p.R96W mutation in the CYP17 gene in a Brazilian patient.

Congenital adrenal hyperplasia (CAH) resulting from 17α-hydroxylase/17,20-lyase deficiency is a rare autosomal recessive disease and the second most common form of CAH in Brazil. We describe the case of a Brazilian patient with CYP17 deficiency (17α-hydroxylase/17,20-lyase deficiency) caused by a homozygous p.R96W mutation on exon 1 of the CYP17 gene, an unusual genotype in Brazilian patients with this form of CAH. The patient, raised as a normal female, sought medical care for lack of pubertal signs and primary amenorrhea at the age of 16 years. At evaluation, the presence of a 46,XY karyotype, hypertension and hypokalemia were observed. We emphasize the recognition of CYP17 deficiency in the differential diagnosis of cases of hypergonadotrophic hypogonadism and hypertension in young patients who need specific treatment for both situations.