VITAMIN D RECEPTOR POLYMORPHISMS (BSMI, TAQI) AND ITS ASSOCIATION WITH SERUM KLOTHO LEVELS IN PATIENTS WITH SCLERODERMA

Scleroderma is a chronic connective tissue disease with unknown etiology. Vitamin D, a necessary hormone that plays a particular function in the calcium and phosphate homeostasis, is involved in etiology of this disorder. Klotho, co-receptor of fibroblast growth factor 23 (FGF-23), can interfere in calcium and phosphate metabolism. The purpose of this study was to determine the relationship of VDR gene polymorphisms (BsmI, TaqI) and serum Klotho levels with scleroderma susceptibility.
90 subjects (60 scleroderma patients and 30 controls) were studied. The BsmI and TaqI polymorphisms of VDR were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method using restriction enzymes BsmI and TaqI. Serum Klotho and vitamin D levels were analyzed by enzyme-linked immunosorbent assay (ELISA).
No significant difference was seen in the genotype frequencies of TaqI polymorphism between the groups (p=0.904), but a significant difference was found between the Scleroderma patients and control groups in BsmI polymorphism frequencies (P = 0.037). Serum levels of Klotho and 25(OH) D in scleroderma patients were lower than those in healthy controls (p˂0.001). There was no significant difference in serum FGF-23 levels between patients and controls (p=0.202).
The results indicate that the BsmI polymorphism in the VDR gene as well as Klotho and vitamin D levels may be associated with the etiology of scleroderma. Further studies are required to apply these associations.