Exome Sequencing for the Diagnosis of 46, XY Disorders of Sex Development

Context: Disorders of sex development (DSD) are clinical conditions where there is a discrepancy between the chromosomal sex and the phenotypic (gonadal or genital) sex of an individual. Such conditions can be stressful for patients and their families and have historically been difficult to diagnose, especially at the genetic level. In particular, for cases of 46, XY gonadal dysgenesis, once variants in SRY and NR5A1 have been ruled out, there are few other single gene tests available. Objective: We used exome sequencing followed by analysis with a list of all known human DSD-associated genes to investigate the underlying genetic etiology of 46, XY DSD patients who had not previously received a genetic diagnosis. Design: Samples were either submitted to the research laboratory or submitted as clinical samples to the UCLA Clinical Genomic Center. Sequencing data were filtered using a list of genes known to be involved in DSD. Results: We were able to identify a likely genetic diagnosis in more than a third of cases, including 22.5% with a pathogenic finding, an additional 12.5% with likely pathogenic findings, and 15% with variants of unknown clinical significance. Conclusions: Early identification of the genetic cause of a DSD will in many cases streamline and direct the clinical management of the patient, with more focused endocrine and imaging studies and better-informed surgical decisions. Exome sequencing proved an efficient method toward such a goal in 46, XY DSD patients.