fgf-23, klotho and vitamin d levels in scleroderma

background: scleroderma is a chronic connective tissue disease of unknown etiology. vitamin d and parathyroid hormone (pth) that play particular functions in calcium and phosphate homeostasis may be involved in the etiology of this disorder. klotho, the co-receptor of the fibroblast growth factor 23 (fgf-23), can interfere with calcium and phosphate metabolism. the purpose of this study was to evaluate serum klotho, fgf-23, intact pth (ipth) and vitamin d levels in scleroderma patients compared with the healthy controls. methods: the study was performed in biotechnology research center, tabriz university of medical sciences (tums) from 2014-2015. sixty scleroderma patients based on the classification criteria of systemic sclerosis and 30 age- and sex-matched healthy controls were included in this study. serum klotho, fgf-23, 25-hydroxy vitamin d (25-oh vit d), and ipth levels were analyzed using elisa. results: serum levels of klotho and 25-oh vit d in the scleroderma patients were lower than those in the healthy controls ( p ˂0.001). in addition, scleroderma patients had higher serum ipth levels than the controls ( p <0.001). there was no significant difference in serum fgf-23 levels between the patients and controls ( p =0.202). conclusion: the decreased serum klotho, 25-oh vit d, and increased ipth levels in the scleroderma patients may be associated with the pathogenesis of this disease and could be considered a future therapeutic target.