Recent studies demonstrated that mutation of a single gene in chromosome 13, which is now widely identified as klotho, causes extensive aging phenotypes including arteriosclerosis, vascular calcifications, soft tissue calcifications, emphysema, hypoactivity, gonadal dysplasia, infertility, skin atrophy, ataxia, hypoglycemia and severe hyperphosphatemia. Here, KL is linked to hyperphosphatemia.