Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 46 4 2017 04 26 530 536 Ravan AHMADI Dept. of Clinical Biochemistry and Laboratory Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Mehrzad HAJIALILO Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Amir GHORBANIHAGHJO Dept. of Clinical Biochemistry and Laboratory Medicine, Tabriz University of Medical Sciences, Tabriz, Iran AND Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Ali MOTA Dept. of Clinical Biochemistry and Laboratory Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Sina RAEISI Dept. of Clinical Biochemistry and Laboratory Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Nasrin BARGAHI Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran Mohammad VALILO Dept. of Clinical Biochemistry and Laboratory Medicine, Tabriz University of Medical Sciences, Tabriz, Iran Farahnaz ASKARIAN Dept. of Clinical Biochemistry and Laboratory Medicine, Tabriz University of Medical Sciences, Tabriz, Iran 2017 04 26 2017 04 26 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.   https://ijph.tums.ac.ir/index.php/ijph/article/view/9763 https://ijph.tums.ac.ir/index.php/ijph/article/download/9763/5633