Sex Assignment and Diagnostics in Infants with Ambiguous Genitalia - A Single-Center Retrospective Study.

Ambiguous genitalia affect 1 in 5,000 live births. Diagnostic procedures can be time-consuming, and often the etiology cannot be established in this group of individuals with differences/disorders of sex development (DSD). We aimed to evaluate the clinical presentation, sex assignment, and diagnostic workup in these patients. In this retrospective observational study, we included infants who presented with ambiguous genitalia from 2006 to 2016 at the Radboudumc (Radboud University Medical Center) DSD expert center. Relevant data were collected from patient records. Sixty-two 46,XY and fourteen 46,XX individuals were included. Sex was assigned in the first days of life and based on the combination of presence or absence of a uterus on ultrasound, AMH level, palpable gonads, and the karyotype (corresponded in 96% of the patients). In 86% of the 46,XX DSD subjects, a diagnosis was made, whereas in only 15/62 (24%) of the 46,XY DSD individuals, etiology was determined. In 52 individuals, genetic testing was performed resulting in a diagnosis in 24 patients (46%). AMH, hCG-stimulated testosterone, and dihydrotestosterone levels contributed to determining etiology, whilst basal testosterone and basal dihydrotestosterone did not. Establishing a diagnosis in infants with ambiguous genitalia is complex and challenging; this study aids to enhance this process and improve current practice.