Mixed Gonadal Dysgenesis: A Narrative Literature Review and Clinical Primer for the Urologist

Purpose: Mixed gonadal dysgenesis is a difference of sex development that is often confused with other conditions. Individuals have a 45,X/46,XY karyotype. Gonads are characterized by a streak gonad and a dysgenetic testis at varying levels of descent. Persistent Müllerian structures are typical (e.g. hemi-uterus). There is significant phenotypic heterogeneity of the internal and external genitalia that, together with different interpretations of the definition, have contributed to a poor understanding of the condition among pediatric urologists. Mixed gonadal dysgenesis is one manifestation of the 45,X/46,XY karyotype. 45,X/46,XY mosaicism can also be associated with typical female or male external genitalia. This review aims to clarify the mixed gonadal dysgenesis definition and to provide urologists with diagnostic and management considerations for affected individuals. Materials and Methods: We searched 3 medical databases for articles related to mixed gonadal dysgenesis. 287 full-text abstracts and manuscripts were reviewed for content pertinent to: (1) Clarifying the definition of mixed gonadal dysgenesis, and (2) Describing the following related to the care of affected individuals: prenatal and neonatal evaluation and management, genital surgery, gonadal malignancy risk and management, fertility, gender dysphoria/incongruence, puberty and long-term outcomes, systemic comorbidities, and transitional care. Results: 50 articles were included. Key points and implications for each of the above topics were summarized. Conclusions: Mixed gonadal dysgenesis exists on a wide phenotypic spectrum and management considerations reflect this heterogeneity. Care for individuals with mixed gonadal dysgenesis is complex, and decisions should be made in a multidisciplinary setting with psychological support.