To improve the recognition and treatment of the combination of classical congenital adrenal hyperplasia (CAH) and Turner′s syndrome. A case of 21-hydroxylase deficiency (21-OHD) in 45, X[3]/46, XX[47] was reported, and the related literatures were reviewed. A 29-year-old woman with 45, X[3]/46, XX[47] was referred with clitorimegaly and primary amenorrhea. Her height was 150 cm with a weight of 56 kg. Physical examination revealed a Tanner stage Ⅵ for both breast development and pubic hair development. She showed a little signs of Turner′s syndrome, such as cubitus valgus. Lab findings: sex hormones are significantly increased, including progesterone, testosterone, dehydroepiandrosterone, 17 hydroxyprogesterone, dihydrotestosterone, and androstendione. Enhanced CT scan showed bilateral adrenal hyperplasia. Gynecological ultrasound showed that the size of the uterus and ovary were near normal and the endometrium was not clear. By gene mutation screening, two mutation sites were found in CYP21A2 gene, such as IVS2-13C/A→G and p. Ile173Asn(c.518T→A). Taken together, the patient was diagnosed as a combination of 21-OHD and Turner syndrome. A total of ten patients associated with CAH in Turner′s syndrome have been reported so far. The findings showed that routine karyotyping during investigations of patients presenting with ambiguous genitalia or with a diagnosis of CAH may reveal the concomitant presence of Turner′s syndrome. We should make a definite diagnosis and give early treatment as soon as possible. (Chin J Endocrinol Metab, 2017, 33: 760-764)

Congenital adrenal hyperplasia; 21-hydroxylase deficiency; Turner′s syndrome; CYP21A2 gene mutation