DNAH6 is a novel candidate gene associated with sperm head anomaly

Globozoospermia and acephalic spermatozoa are two rare sperm head anomalies associated with male infertility. Combination of the two phenotypes in the same patient is extremely rare, so the underlying pathogenesis of this disorder remains unclear. Here, we report a 35-year-old infertile male, who presented with 30% of sperm-lacked heads and 69% of sperm round-headed or small-headed with neck thickening in his ejaculate. Subsequent whole-exome sequencing (WES) analysis identified compound heterozygous variants within the DNAH6 gene. DNAH6 is a testis-specific-expressed protein that was localised to the neck region in the spermatozoa of normal control; however, immunofluorescent staining failed to detect DNAH6 protein in the patient's spermatozoa. Quantitative real-time PCR analysis also showed the complete absence of DNAH6 mRNA in the patient's spermatozoa. Moreover, two cycles of in vitro fertilisation (IVF)-assisted reproduction were carried out, but pregnancy was not achieved after embryo transfer. Therefore, rare sequence variants in DNAH6 might be susceptibility risks for human sperm head anomaly.