Two Novel TEX15 Mutations in a Family with Nonobstructive Azoospermia

Aim: Genetic investigations explain only a small percentage of cases of nonobstructive azoospermia (NOA), a condition that affects up to 2% of infertile couples. This study aimed to identify further genomic variants that are associated with primary spermatogenic failure within the testis. Methods: One family with 2 infertile siblings affected by NOA was genotyped by whole-exome sequencing. DNA variants were filtered based on quality score, allele frequency, and functional roles of genes in spermatogenesis. Results: Both NOA males were compound heterozygotes for a nonsense mutation and a single nucleotide deletion leading to premature stop codons in the TEX15 gene (c.2419A>T, p.Lys807*, and c.3040delT, p.Ser1014Leufs*5, respectively). The single mutations were identified only on one allele in 6 family members, including 3 fertile males who conceived naturally. Conclusion: This is the second reported case of a TEX15 deleterious mutation cosegregating with NOA in a family in which the infertile phenotype is reminiscent of the one observed in the TEX15-knockout mouse, confirming that TEX15 plays a critical role in normal spermatogenesis and its defects may be responsible for a number of NOA cases. (C) 2017 S. Karger AG, Basel