46,XY 17 alpha-hydroxylase/17,20 lyase deficiency with breast development: A case report and literature review.

Individuals with the 46,XY karyotype and 17 alpha-hydroxylase/17,20 lyase deficiency (17OHD) may develop disorders/differences of sex development (DSD) accompanied by delayed puberty or primary amenorrhea. Glucocorticoid replacement is required to normalize hypertension in 17OHD, which highlights the importance of appropriate diagnostics for the selection of relevant treatment. A 16-year-old female with primary amenorrhea was found to have the 46,XY karyotype. Since the patient had spontaneous breast development, she was initially diagnosed with complete androgen insensitivity syndrome (CAIS). However, CAIS was subsequently ruled out due to an extremely low testosterone level, and 17OHD was suspected because of hypertension with low plasma renin activity, an elevated adrenocorticotropic hormone (ACTH) level, and decreased cortisol level. Two variants in CYP17A1, which were previously reported to be pathogenic, were detected and eventually confirmed the diagnosis of 17OHD. We reviewed 198 reported cases of 46,XY with 17OHD, and found spontaneous breast development in 9 of 129 (7.0%) individuals with typical female external genitalia. Although gonadal hormone production is impaired in 17OHD, 17OHD needs to be considered in differential diagnostics of 46,XY DSD even with spontaneous breast development.