Clinical characteristics and mutation analysis of two Chinese children with 17a-hydroxylase/17,20-lyase deficiency.

Combined with the literature, recognize the clinical features and molecular genetic mechanism of the disease. 17a-hydroxylase/17,20-lyase deficiency, a rare form of congenital adrenal hyperplasia, is caused by mutations in the cytochrome P450c17 gene (CYP17A1), and characterized by hypertension, hypokalemia, female sexual infantilism or male pseudohermaphroditism. We presented the clinical and biochemical characterization in two patients (a 13 year-old girl (46, XX) with hypokalemia and lack of pubertal development, a 11 year-old girl (46, XY) with female external genitalia and severe hypertension). CYP17A1 mutations were detected by PCR and direct DNA sequencing in patients and their parents. A homozygous mutation c.985_987delTACinsAA (p.Y329KfsX418) in Exon 6 was found in patient 1, and a homozygous deletion mutation c.1459_1467delGACTCTTTC (p.Asp487_Phe489del) in exon 8 in patient 2. The patients manifested with hypertension, hypokalemia, sexual infantilism should be suspected of having 17a-hydroxylase/17,20-lyase deficiency. Definite diagnosis is depended on mutation analysis. Hydrocortisone treatment in time is crucial to prevent severe hypertension and hypokalemia.