Genetic Evidence of the Association of DEAH-Box Helicase 37 Defects with 46,XY Gonadal Dysgenesis Spectrum

Abstract

Context: 46,XY Gonadal dysgenesis (GD) is a heterogeneous group of disorders with a wide phenotypic spectrum, including embryonic testicular regression syndrome (ETRS). Objective: To report a gene for 46,XY GD etiology, especially for ETRS. Design: Screening of familial cases of 46,XY GD using whole-exome sequencing and sporadic cases by target gene-panel sequencing. Setting: Tertiary Referral Center for differences/disorders of sex development (DSD). Patients and Interventions: We selected 87 patients with 46,XY DSD (17 familial cases from 8 unrelated families and 70 sporadic cases); 55 patients had GD (among them, 10 patients from 5 families and 8 sporadic cases had ETRS), and 32 patients had 46,XY DSD of unknown etiology. Results: We identified four heterozygous missense rare variants, classified as pathogenic or likely pathogenic in the Asp-Glu-Ala-His-box (DHX) helicase 37 (DHX37) gene in five families (n = 11 patients) and in six sporadic cases. Two variants were recurrent: p.Arg308Gln (in two families and in three sporadic cases) and p.Arg674Trp (in two families and in two sporadic cases). The variants were specifically associated with ETRS (7/14 index cases; 50%). The frequency of rare, predicted-to-be-deleterious DHX37 variants in this cohort (14%) is significantly higher than that observed in the Genome Aggregation Database (0.4%; P < 0.001). Immunohistochemistry analysis in human testis showed that DHX37 is mainly expressed in germ cells at different stages of testis maturation, in Leydig cells, and rarely in Sertoli cells. Conclusion: This strong genetic evidence identifies DHX37 as a player in the complex cascade of male gonadal differentiation and maintenance.