A novel loss-of-function variant in <i>DNHD1</i> linked to human asthenozoospermia

Objective: Asthenozoospermia, characterized by diminished sperm motility, shows substantial genetic heterogeneity. Although many familial cases of asthenozoospermia have been documented, the genetic etiology for most affected males remains unknown. Methods: This study used clinical and molecular approaches to characterize a hereditary form of asthenozoospermia. Two patients born to consanguineous parents exhibited impaired sperm motility. Whole-genome sequencing (WGS), followed by Sanger sequencing, was performed for molecular diagnosis and was coupled with three-dimensional protein modeling to characterize the identified variant. Results: WGS revealed that both affected brothers carried a pathogenic variant (c.580C>T; p.Gln194*) in dynein heavy chain domain 1 (DNHD1). Homozygous variants in DNHD1 have previously been linked to spermatogenic failure 65 (Online Mendelian Inheritance in Man [OMIM] 619712). Three-dimensional protein modeling demonstrated significant alterations in DNHD1 secondary structure that could contribute to loss-of-function. Conclusion: These findings support a role for DNHD1 in maintaining the structural and functional integrity of sperm. Accurate molecular diagnosis may facilitate genetic counseling and inform clinical management.