Systemic lupus erythematosus (SLE) is an autoimmune disorder with heterogeneous clinical manifestations and target tissue damage. Currently, several genes have been associated with SLE susceptibility, including vitamin D receptor (VDR), which is a mediator of immune responses through the action of vitamin D. Polymorphisms in the VDR gene can impair the vitamin D (D3) function role, and since SLE patients show deficient D3 blood levels, it leads to a possible connection to the disease's onset. In our study we searched for an association between VDR polymorphisms and risk of developing SLE, as well as the disease's clinical manifestations. We enrolled 158 SLE patients and 190 Southeast Brazilian healthy controls, genotyped for five Tag single nucleotide polymorphisms (SNPs), covering most of the VDR gene region. We found an association between VDR SNPs and SLE for the following clinical manifestations: rs11168268 and cutaneous alterations (p=0.036), rs3890733 (p=0.003) rs3890733 and arthritis (p=0.001), rs2248098 and immunological alterations (p=0.040), rs4760648 and antibody anti-dsDNA (p=0.036). No association was reported between VDR polymorphisms and SLE susceptibility.

ABSTRACT. The aim of this study was to perform an association study between seven Fyn-binding protein gene (FYB)-tag single nucleotide polymorphisms (SNPs) and type I diabetes mellitus (T1DM), as well as with disease age of onset. We also assessed the role of FYB SNPs in the insurgence of autoimmune polyglandular syndrome type III (APSIII), characterized by the simultaneous presence of autoimmune thyroid disease and celiac disease, in patients with T1DM from a Northeastern Brazilian population. One hundred and seventy-seven patients with T1DM and 190 healthy individuals were genotyped for seven tag SNPs, covering most of the FYB locus, using real-time polymerase chain reaction amplification. There was no significant difference in the distribution of allele and genotype frequencies among patients and healthy individuals. Moreover, none of the tag SNPs were associated either to T1DM age of onset or to the insurgence of APSIII. However, since the FYB protein is a key component in T cell response, its gene variants might play a role in protein function, which might be testable in a population with different genetic backgrounds or by using functional assays.