A novel candidate missense variant in the catalytic domain of USP26 associated with asthenoteratozoospermia.

INTRODUCTION

Teratozoospermia, characterized by abnormal sperm morphology, is a significant factor contributing to the male infertility. Deubiquitinating enzymes play a crucial role in controlling protein synthesis and degradation during spermatogenesis.

METHODS

Whole exome sequencing (WES) and the following insilico analysis were performed to detect the associated variant with asthenoteratozoospermia in a consanguineous Iranian family with two affected brothers.

RESULTS

WES identified a novel candidate hemizygous missense mutation (chrX-132161044 T > G:NM_031907.2:c.1205A > C, p.Asn402Thr) in the catalytic domain of the USP26 (Ubiquitin-Specific Peptidase 26) deubiquitinating enzyme in two affected siblings. The USP26 encodes a testis-specific deubiquitinating enzyme which is necessary for normal spermatogenesis and may influence male fertility. The mutation changes asparagine 402 (N) into threonine (T) and was co-segregated with phenotype in other available family members. In-silico predictions indicate that the N402T change not only leads to the absence of a hydrogen bond between the mutant N402T and F430 residues but also causes a reduction in USP26 protein stability, potentially resulting in defects in USP26 enzymatic activity.

CONCLUSIONS

Our findings support a potential role for USP26 variants contributing to asthenoteratozoospermia.