A practical approach to ambiguous genitalia in the newborn period.

The evaluation and management of neonates with ambiguous genitalia requires sensitivity, efficiency, and accuracy. The approach to these neonates is facilitated by a multidisciplinary team including urology, endocrinology, genetics, and psychiatry or psychology. Disorders of sex development (DSD) encompass chromosomal DSD, 46,XX DSD, and 46,XY DSD. The 46,XX DSD is the most common DSD and in the majority of these children congenital adrenal hyperplasia is the underlying etiology. The 46,XY DSD is a heterogeneous disorder that often results from a disruption in the production or response to testosterone, dihydrotestosterone, or Mullerian inhibitory substance. Chromosomal DSD includes conditions resulting from abnormal meiosis, including Klinefelter syndrome (47, XXY) and Turner syndrome. The evaluation of children with DSD demands a thorough physical examination, medical history, karyotype, metabolic panel, 17-OH progesterone, testosterone, luteinizing hormone, follicle stimulation hormone, and urinalysis. A radiographic evaluation should begin with an abdominal and pelvic ultrasound but may include magnetic resonance imaging, endoscopy, or laparoscopy.