The role of BsmI and FokI vitamin D receptor gene polymorphisms and serum 25-hydroxyvitamin D in Brazilian patients with systemic lupus erythematosus

• Published in: Lupus Vol. 21; no. 1; pp. 43 - 52
• Main Authors: Monticielo, OA, Brenol, JCT, Chies, JAB, Longo, MGF, Rucatti, GG, Scalco, R, Xavier, RM
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01-01-2012; Sage Publications Ltd
• Subjects: Adult; Brazil; Case-Control Studies; Deoxyribonucleases, Type II Site-Specific - metabolism; Disease; European Continental Ancestry Group; Female; Genetic Predisposition to Disease; Genotype; Genotype & phenotype; Hospitals; Humans; Immune system; Internal medicine; Investigations; Laboratories; Lupus; Lupus Erythematosus, Systemic - blood; Lupus Erythematosus, Systemic - genetics; Male; Middle Aged; Polymorphism; Polymorphism, Genetic; Receptors, Calcitriol - genetics; Rheumatology; Vitamin D; Vitamin D - analogs & derivatives; Vitamin D - blood; Vitamin deficiency; Brazil; Rio Grande do Sul Brazil; BsmI polymorphism; systemic lupus erythematosus; 25-hydroxyvitamin D; FokI polymorphism; vitamin D; vitamin D receptor; genetics and immunology
• ISSN: 0961-2033; 1477-0962
• DOI: 10.1177/0961203311421798

Vitamin D deficiency has been described in systemic lupus erythematosus (SLE). BsmI VDR (vitamin D receptor) gene polymorphism was associated with SLE in Asian patients. Studies in Brazilian populations have not been realized. A case-control study with 195 SLE patients and 201 healthy controls was conducted to investigate the influence of BsmI and FokI VDR gene polymorphisms on susceptibility to SLE. In addition, 25-hydroxyvitamin D [25(OH)D] was measured in SLE patients to evaluate possible associations with VDR polymorphic variants and clinical and laboratory expressions of disease. Genotyping was performed by RFLP-PCR. The measurement of 25(OH)D was performed by chemiluminescence. There was no statistically significant difference in genotype and allelic frequencies of BsmI and FokI polymorphisms between European-derived cases and controls. The mean serum levels of 25(OH)D were 25.51 ± 11.43 ng/ml in SLE patients. According to genotype distribution, 25(OH)D concentrations were significantly higher in patients carrying the FokI f/f genotype compared with patients carrying the F/F genotype (31.6 ± 14.1 ng/ml versus 23.0 ± 9.2 ng/ml, p = 0.004), reinforcing its role in the functional activity of VDR. This feature may be considered in future clinical and experimental studies involving vitamin D measurements. Therefore, genetic-specific definitions of ideal levels of vitamin D in SLE need to be established in future studies.