46,XY Gonadal Dysgenesis Due to NR0B1 Duplication: A Systematic Review

Objective Gonadal dysgenesis (GD) due to NR0B1 duplication is a subset of 46,XY disorder of sexual differentiation (DSD) characterised by variable external genitalia phenotypes ranging from complete GD (CGD) to partial GD (PGD) and may have syndromic associations. The DSD‐phenotype spectrum and its correlation with genotype have not been systematically studied. Design A systematic review of 46,XY GD with NR0B1 duplication ( n = 47, including two patients from our centre) was conducted to understand DSD phenotypes and their genotypic correlations. Results Large and submicroscopic duplications were observed in 61.7% and 38.3%, respectively, and maternal inheritance (asymptomatic carriers, except one) was reported in 63.3%. Median age at presentation was 1.0 (birth to 38) years, and syndromic manifestations were the cause in 55.3% and gonadal dysfunction‐related symptoms in 42.5%. CGD, PGD, and typical male genitalia were seen in 66%, 27.7%, and 6.4%, respectively. Gender incongruence and fertility (except for one reported paternity) have not been reported. Gonadoblastoma and gonadal germ cell cancer were noted in 17% (median age: 11 years) and 2.1% (15 years of age) of cases, respectively. Compared with submicroscopic duplications, large duplications were associated with earlier presentation (0.7 vs. 15 years; p = 0.008) and higher prevalence of syndromic features (96.6% vs. 22.2%; p = 0.0001), while external genital phenotype, cryptorchidism, presence of mullerian structures, and gonadoblastoma rates were comparable. Conclusions 46,XY GD phenotype with NR0B1 duplication does not correlate with duplicated segment size. A delineated spectrum of gonadal dysfunction, gender identity, fertility, and gonadal malignancy risk presented here can help to optimise patient management.