Genotype–phenotype Correlations, Surgical Selections, and Postoperative Complications of 5Α-Reductase 2 Deficiency in 69 Children with Hypospadias

5α-reductase 2 deficiency prevents testosterone from being converted to dihydrotestosterone, which causes abnormal urogenital sinus development. The aim of this study was to analyze the relationship between genotype–phenotype, surgical selections, and postoperative complications of 5α-reductase 2-deficient patients with hypospadias. We retrospectively evaluated the medical records of patients who were diagnosed with 5α-reductase 2 deficiency after genetic testing in the Department of Endocrinology and underwent initial hypospadias surgery in the Department of Urology in Beijing Children’s Hospital, Capital Medical University (Beijing, China), from April 2007 to December 2021. A total of 69 patients were included in this study; the mean age at surgery was 34.1 months, and the average follow-up time was 54.1 months. Sixty children were treated with preoperative hormone stimulation (PHS) to promote penile growth. The average penis length and glans width were increased by 1.46 cm and 0.62 cm, respectively. The most frequent mutations were p.R227Q (39.1%, 54/138), p.Q6* (15.2%, 21/138), p.G203S (12.3%, 17/138), and p.R246Q (11.6%, 16/138). In 64 patients who were followed up, 43 had a one-stage operation and 21 had a staged operation, and there were significant differences in external masculinization score (EMS) ( P = 0.008) and the average number of operation required to cure ( P < 0.001) between one-stage and staged operations. PHS had a positive effect ( P < 0.001) on penile development. The p.R227Q mutation was associated with higher EMS and less severe hypospadias. One-stage surgery can be selected if conditions permit. The growth and development of children are acceptable in the long term, but penis growth remains unsatisfactory. Long-term complications of hypospadias should be considered during puberty.