Xu et al., reported a lower expression of SPAG6 in spermatozoa from men harboring SPAG6 variants and suggested that SPAG6 variants are a potential pathogenic factor for syndromic severe asthenozoospermia and the non-syndromic asthenoteratozoospermia-associated MMAF phenotype [50]. Here, SPAG6 is linked to Reduced sperm motility.