ESPE Abstracts

Background: Patients with 45,X/46,XY mixed gonadal dysgenesis (MGD) have variable phenotypes leading to both male and female sex assignments. A multidisciplinary team should guide the process of sex assignment, however a standardized approach may provide objective guidance for the team as well as a tool for settings without such resources. One of the most important considerations for sex assignment is the hormonal production, which often determines the degree of virilization. Therefore, the first step to standardization is to establish a virilization score.

Objective and hypotheses: To develop a virilization score for sex assignment in patients with 45,X/46,XY MGD.

Method: Using the external genitalia score previously published by Ahmed et al, we developed a compounded virilization score with nine parameters describing external genitalia, internal structures and gonads. The score was applied retrospectively to 22 patients with 45,X/46,XY MGD and abnormal external genitalia from one institution and validated with 8 patients from a second institution. ROC curves were used to establish a cut off value above which the patients were more likely to be assigned male and a logistic regression model was used to determine the importance of its components.

Results: Eighteen of the 30 included patients received male sex assignments. The percentages of Y containing cell lines were similar in patients with either sex assignment. ROC analysis showed an AUC of 0.995. When using 9 as the cut off value, the score matched the current sex assignment in 29 out of the 30 patients (96%, 95% CI: 0.83–0.99). All the components were important, with urethral position being the most significant.

Conclusion: Sex assignment for individuals with 45,X/46,XY MGD is complex. However a virilization score may be used to simplify, standardize, and reduce variability within this process. Prospective studies using a larger sample are needed to validate its utility.