ESPE Abstracts

Background: The steroidogenic Factor 1 (SF1, NR5A1) is one of the key factors involved in gonadal and adrenal development and steroidogenesis. Until now, over 50 mutations were described in different phenotypes of XY disorders of sex development (DSD) such as complete gonadal dysgenesis, severe and mild partial gonadal dysgenesis, hypospadias, infertility and bilateral anorchia. So far, no genotype-phenotype correlation could be demonstrated.

Objective and hypotheses: To investigate genotype-phenotype correlation SF1-mutations by functional in-vitro studies.

Method: Investigation of the transcriptional activity of different SF1 missense mutations on central promoters of gonadal development in a homogeneous experimental set up by Dual-Glo luciferase assays in HEK and Sertoli cells. Mutations of different structural region from patients with phenotypes ranging from infertility to complete gonadal dysgenesis were chosen. TESCO, the initiator of testis determination and the promoters of CYP11A1, reflecting steroidogenesis and Leydig cell function and AMH representing Sertoli cell function were used as reporter.

Results: SF1 missense mutations in the DNA-binding (p.E35G, p.R62C) and ligand-binding domain (p.L376F) leading to partial and complete gonadal dysgenesis showed a significant reduced ability to activate TESCO and the CYP11A1 promoter. SF1 mutations in the hinge-region (p.P131L, p.P191C) leading to infertility showed only moderate reduced ability to activate TESCO and minor reduced activation of the CYP11A1 promoter. None of the mutations did show significant reduction of transcriptional activity of the AMH promoter.

Conclusion: The transcriptional activity of the different SF1 mutations on the TESCO and CYP11A1 promoter reflect the severity of clinical expression of gonadal dysgenesis and steroidogenic function in-vitro. Functional studies of SF1 mutations using TESCO and the CYP11A1 promoter can be helpful predictive models for phenotypes in-vitro.