PLCZ1 and Infertility: For example, in a cohort of 35 infertile men with grade II–III varicocele, PLCZ1 transcript and PLCζ protein levels in sperm were significantly reduced—by approximately 50%—compared to those in 20 fertile men, as measured by RT-PCR and Western blot, likely due to oxidative stress impairing spermatogenic cells in the testes [54].