NTRK2 and Infertility: Likewise, oocyte-specific ablation of Ntrk2 resulted in complete POI by 14 weeks, with total disintegration of follicular structure and oocyte loss (Dorfman et al., 2014), while genetic elimination of the enzymatic machinery for the synthesis of complex O- and N-glycans in the oocyte resulted in subfertility already by 6 weeks, and complete ovarian failure and infertility between 9 and 11 weeks of age (Williams and Stanley, 2011; Grasa et al., 2016).