A novel splicing variant in DNAH8 causes asthenozoospermia.

PURPOSE To identify the genetic factors responsible for asthenozoospermia, which is a major cause of male infertility characterized by immotile and malformed spermatozoa. METHODS Whole-exome sequencing was performed in two brothers from a family with asthenozoospermia to identify pathogenic variants. The functional effect of the identified variant was investigated in HEK293T cells using a minigene assay. RESULTS We identified a novel homozygous splicing variant c.6311-2A>G in DNAH8 from two affected brothers belonging to the same consanguineous family. The splicing variant altered a consensus splice acceptor site of DNAH8 intron 44, which led to the deletion of exon 45 and resulted in a frameshift and a predicted truncated protein (p.G2104Efs*19). Although most spermatozoa from the patients presented with reduced sperm motility, intracytoplasmic sperm injection was able to overcome the inability of the spermatozoa to reach the ovum and thus produce a healthy child for the proband. CONCLUSIONS This finding expands the mutational spectrum of DNAH8, making it a potential genetic diagnostic marker for those suffering from primary male infertility.