Abstract: Objective To study the clinical features and the results of CYP11B1 gene analysis of a Chinese adult with classical 11β-hydroxylase deficiency. Methods One case diagnosed with classical 11β-hydroxylase deficiency in our department in 2016 was enrolled in this study. The clinical characteristics, diagnosis, treatment and gene analysis were reported and the related literature was reviewed. Results The male patient, 29 years old, paroxysmal paralysis for more than 20 years with accelerated skeletal maturation, resultant short stature and peripheral precocious puberty. CT showed bilateral adrenal occupying lesions. Laboratory examinations found plasma ACTH 301.70 pg/mL,serum 17α-hydoxy progesterone 23.83 ng/mL, testosterone 997.04 ng/dL, dehydroepiandrosterone sulfate 921.70 g/dL, androstenedione >10.30 ng/mL, orthostatic renin activity 1.90 μIU/(mL·h), aldosterone / renin activity 0.72. Dexamethasone 0.75 mg/d(bedtime)combined with compound reserpine triamterene tablets was given to the patient which effectively inhibit ACTH and androgen levels and blood pressure. A novel splicing mutation c.595+1G>A was identified in CYP11B1 gene of the patient. The mutation of the patient was homozygous and his mother and sister was heterozygous, while his father was not identified with this mutation. Conclusion Glucocorticoid combined with reserpine triamterene tablets can be used in the classical 11β-hydroxylase deficiency. A novel homozygous mutation c.595+1G>A was related to the classical phenotype.

Key words: Mutation, Congenital adrenal hyperplasia, 11β-hydroxylase deficiency, CYP11B1, Gene