On the other hand, the loss of FGF-23 in mice (FGF-23−/− mice) exhibits elevated levels of serum phosphate, calcium, and 1,25-(OH)2D. Interestingly, despite the high systemic levels of mineral ions, these mice experience severe defects in skeletal mineralization (and other phenotypic manifestations, such as infertility, extensive soft tissue calcifications, muscle wasting, and profound growth retardation). Here, FGF23 is linked to Infertility.