ESPE Abstracts (2016) 86 P-P2-400

Novel CYP17A1 Mutation and CYP21 Mutations in Two Siblings

Emregül Işıka, Mehmet Keskinb & Ahmet Yeşilyurtc


aGaziantep Children’s Hospital, Pediatric Endocrinology, Gaziantep, Turkey; bGaziantep University Faculty of Medicine, Pediatric Endocrinology, Gaziantep, Turkey; cDışkapı Yıldırım Beyazıt Training and Research Hospital, Genetics, Ankara, Turkey


Background: 17 hydroxylase deficiency is a rare form of congenital adrenal hyperplasia resulting from loss-of-function mutations involving the CYP17 gene. It is characterized by decreased production of glucocorticoids and sex steroids and increased synthesis of mineralocorticoid precursors.

Objective and hypotheses: We aimed to identify genetic cause of lack of puberty in a girl and the cause of ambiguous genitalia in her sibling. Fourteen-year-old girl presented with lack of telarche. Parents were first degree cousins. On physical examination, weight was 37 kg (−2.8 SDS), height was 152.5 cm (−1.3 SDS), puberty was Tanner stage 1. Blood pressure was 120/90 mmHg. Bone age was 10 years. Laboratory results were as follows; serum Na: 140 mmol/l, K: 3.6 mmol/l, glukoz: 95 mg/dl, FSH: 94 ıu/l, LH: 63 ıu/l, estradiol: 11.8 pg/ml, PRL: 9.3 ng/ml, ACTH: 1250 pg/ml (0–46), cortisol: 0.5 μg/dl, total testosteron: 10 ng/dl, progesteron: 12.7 ng/ml, pH: 7.34, HCO3: 26.4 mmol/l. Uterus and ovaries were not visualized. Chromosomal analysis was 46 XY. Her newborn sibling was consulted for ambiguous genitalia. Phallus was 2.5 cm with no palpable gonads. Laboratory results showed 17 hidroksiprogesteron:215 ng/ml, total testosteron: 245 ng/dl, 1–4 androstenedion >10 ng/ml. Chromosomal analysis was 46 XX.

Method: Gene analysis was undertaken as described before.

Results: CYP17A1 gene analysis showed novel homozygous c.617_618delTA mutation in exon 3. Parents and siblings were heterozygous. Gene analysis of her newborn sibling showed homozygous CYP21 c.293-13A/C>G (In2G) mutation.

Conclusion: 17 hydroxylase deficiency causes ambiguous genitalia in 46 XY individuals while sexual infantilism is seen in 46 XX patients secondary to decreased production of sex steroids. Different types of congenital adrenal hyperplasia can be seen in the same family specially in areas where consanguineous marriages are frequent.

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