SYCE1 and Infertility: Finally, SYCE1 has been implicated in human infertility, with mutations giving rise to premature truncation or haploinsufficiency having been identified in cases of non-obstructive azoospermia and premature ovarian failure (de Vries et al. 2014; Geisinger and Benavente 2016; McGuire et al. 2011).