USP26 and male infertility: The c.370-371insACA, c.494T>C, c.1423C>T, c.1090C>T, c.1737G>A cluster, with five USP26 mutations, have no effect on deubiquitinating enzyme activity, and enzyme activity and meta-analyses revealed that there is no direct correlation between USP26 mutation and male infertility [13].