Context: The genetic basis of human sex development is slowly being elucidated and more than 40 different genetic causes of differences (or disorders) of sex development (DSD) have now been reported. However, reaching a specific diagnosis using traditional approaches can be difficult, especially in adults where limited biochemical data may be available. /
Objective: We used a targeted next-generation sequencing approach to analyze known and candidate genes for DSD in individuals with no specific molecular diagnosis. /
Partcipants and Design: We studied 52 adult 46,XY women attending a single-center adult service, who were part of a larger cohort of 400 individuals. Classic conditions such as17β-hydroxysteroid dehydrogenase deficiency type 3, 5α-reductase deficiency type 2 and androgen insensitivity syndrome were excluded. The study cohort had broad working diagnoses of complete gonadal dysgenesis (CGD) (n=27) and partially-virilised 46,XY DSD (pvDSD) (n=25), a group that included partial gonadal dysgenesis (PGD) and those with a broad ”partial androgen insensitivity syndrome” label. Targetted sequencing of 168 genes was undertaken. /
Results: Overall a likely genetic cause was found in 16/52 (30.8%) individuals (22.2% CGD; 40.0% pvDSD). Pathogenic variants were found in SRY (n=3), DMRT1 (n=1), NR5A1/SF-1 (n=1) and DHH (n=1) in the CGD group, and in NR5A1 (n=5), DHH (n=1) and DHX37 (n=4) in the pvDSD group. /
Conclusions: Reaching a specific diagnosis can have clinical implications and provides insight into the role of these proteins in sex development. Next-generation sequencing approaches are invaluable, especially in adult populations or where diagnostic biochemistry is not possible
