Fetub, knockout mice, however, do not display these defects, and instead show female infertility (Dietzel et al., 2013); and mammalian Fetuin-B, unlike Fetuin-A, appears to function as a specific inhibitor of meprin and ovastacin metalloproteinases (Karmilin et al., 2019). The gene discussed is FETUB; the disease is female infertility.