Next-Generation Sequencing Reveals Novel Genetic Variants (SRY, DMRT1, NR5A1, DHH, DHX37) in Adults With 46,XY DSD.

CONTEXT: The genetic basis of human sex development is slowly being elucidated, and >40 different genetic causes of differences (or disorders) of sex development (DSDs) 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 DSDs in individuals with no specific molecular diagnosis. PARTICIPANTS 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 as17ß-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 virilized 46,XY DSD (pvDSD) (n = 25), a group that included partial gonadal dysgenesis and those with a broad "partial androgen insensitivity syndrome" label. Targeted sequencing of 180 genes was undertaken. RESULTS: Overall, a likely genetic cause was found in 16 of 52 (30.8%) individuals (22.2% CGD, 40.0% pvDSD). Pathogenic variants were found in sex-determining region Y (SRY; n = 3), doublesex and mab-3-related transcription factor 1 (DMRT1; n = 1), NR5A1/steroidogenic factor-1 (SF-1) (n = 1), and desert hedgehog (DHH; n = 1) in the CGD group, and in NR5A1 (n = 5), DHH (n = 1), and DEAH-box helicase 37 (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.

A case of stiff-person syndrome, type 1 diabetes, celiac disease and dermatitis herpetiformis.

Antibodies against glutamic acid decarboxylase (GAD) are involved in the pathophysiology of stiff-person syndrome (SPS) and type 1 diabetes. GAD catalyses the conversion of glutamate to gamma-aminobutyric acid (GABA). GABA acts as a neurotransmitter between neurones, while in pancreatic beta cells it plays an integral role in normal insulin secretion, hence the clinical presentation of muscular spasms in SPS and insulin deficiency in diabetes. Despite this apparent major overlap in pathophysiology, SPS only rarely occurs in individuals with type 1 diabetes. We report the case of a 41-year-old man presenting with a simultaneous diagnosis of both these conditions. His case is unusual in that it is the first reported case in the literature of these conditions occurring in someone with celiac disease (CD) and dermatitis herpetiformis. We discuss why SPS and type 1 diabetes co-exist in only a minority of cases and speculate on the underlying mechanism of the association with CD and dermatitis herpetiformis in our patient.