Vitamin D receptor (VDR) gene polymorphisms and expression profile influence upon the immunological imbalance in Turner syndrome.

PURPOSE: Turner syndrome (TS) patients display considerable immune misregulation, and it is hypothesized that Vitamin D (VTD) activity may fluctuate according to Vitamin D receptor (VDR) polymorphisms and/or expression profile. To uncover a possible relationship between VDR genotype and clinical conditions in TS patients, we investigated two functional VDR variants (Cdx-2 and FokI) for allele and genotype frequencies, as well as expression profile in TS individuals versus healthy controls (HC). METHODS: We performed a genetic association study including 100 TS patients and 116 HC. Genotyping for VDR Cdx-2 G > A (rs11568820) and FokI C > T (rs2228570) was performed using Taqman Genotyping Assays. VDR gene expression was also evaluated in 15 TS and 15 HC, using fluorogenic probes by qPCR. Statistical analyses were performed using nonparametric Mann-Whitney test, with a 5% significance level (p < 0.05) to uncover differences between groups. In addition, we investigated whether shifted VDR mRNA levels were associated with Cdx-2 and FokI variants in TS patients. RESULTS: We detected a significantly higher frequency of T allele (p = 0.006) as well as T/T genotype (p = 0.01) for FokI in TS patients when compared to HC. When assessing VDR expression, we identified a downregulation in TS woman (- 2.84 FC) versus HC (p < 0.001). Furthermore, C/T (11.24 FC; p = 0.01) and T/T (9.20 FC; p = 0.01) FokI genotypes were upregulated when compared to C/C reference genotype. CONCLUSION: TS patients show different distribution of FokI polymorphism. Downregulation of VDR gene expression may contribute to immunological imbalance in TS.

Vitamin D receptor (VDR) polymorphisms are associated to spontaneous preterm birth and maternal aspects.

Preterm birth (PTB) is featured by less than 37weeks of gestational age or fewer than 259days since the first day from the last menstrual period. Complications of PTB are the major cause of neonatal deaths, several factors are linked to PTB increased risk including immunological and genetics. Vitamin D plays an important role in immune response modulation and its action occurs through the vitamin D receptor (VDR), which recently has been described as overexpressed in human placenta during the pregnancy. Herein we assessed two single nucleotide polymorphisms (SNPs) FokI (rs2228570 A>G) and Cdx-2 (rs11568820 T>C), within VDR, using TaqMan fluorogenic probes, and differential susceptibility to SPTB. We assessed 104 pregnant women with SPTB and 85 women with normal birth in a Northeastern Brazilian population. Statistically significant differences for both SNPs where found when comparing allele and genotype frequencies in both groups: the T allele for rs2228570 and A allele for rs11568820 were significantly more frequent in SPTB group than in normal birth group (p=0.000013 and p=0.00466, respectively). The rs11568820 A/A genotype was associated to clinical/demographic variables such as: premature birth (p=0.007), neonate weight (p=0.039), presence of infection during pregnancy (p=0.011) and premature birth among multiparous (p=0.015). The rs2228570 T/T genotype associated with gestational diabetes mellitus (p=0.044) and chorioamnionitis during pregnancy (p=0.043). In conclusion our findings indicate an association between polymorphisms FokI and Cdx-2 within VDR gene and SPTB, suggesting their involvement in the triggering of these syndromes.

Polymorphisms in key bone modulator cytokines genes influence bisphosphonates therapy in postmenopausal women.

Osteoporosis is a multifactorial and debilitating disease resulting from decreased bone mineral density (BMD) and loss of tissue microarchitecture. Ineffective therapies may lead to bone fractures and subsequent death. Single nucleotide polymorphisms (SNPs) in key immune regulator genes have been associated with therapeutic response to bisphosphonates, which are the first therapeutic line of choice for osteoporosis. However, cytokine pathways and their relation with therapeutic adhesion remain to be fully elucidated. Aimed at better understanding these processes, we investigated the response to bisphosphonate therapy in postmenopausal women and four SNPs in key proinflammatory cytokines genes: IL23R +2284 (C>A) (rs10889677), IL17A +672 (G>A) (rs7747909), IL12B +1188 (T>G) (rs3212227) and INF-γ -1616 (G>A) (rs2069705). A total of 69 patients treated with bisphosphonate were followed for a period of 1 up to 4 years, genotyped and compared according to their changes in bone mineral density (BMD) and level of biochemical markers during their treatment. The INF-γ -1616 G/G associated with increased BMD values in femoral neck (GG/AA, p = 0.016) and decreased BMD values in total hip (GG/GA, p = 0.019; GG/AA, p = 0.011). In relation to biochemical markers, INF-γ -1616 SNP associated with increased alkaline phosphatase (GG/AA; p < 0.0001) and parathyroid hormone levels (AA/GA; p = 0.017). Vitamin D values changes were related to IL17A +672 (GG/GA, p = 0.034) and to IL12B +1188 (TT/TG, p = 0.046) SNPs. Besides, significant differences in changes of calcium levels correlated with IL23R +2284 (CC/CA, p = 0.016) genotypes. Altogether, we suggest that these polymorphisms may play an important role for therapeutic decisions in osteoporosis treatment.

Short Communication FYB polymorphisms in Brazilian patients with type I diabetes mellitus and autoimmune polyglandular syndrome type III.

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.

Meta-analysis of STAT4 and IFIH1 polymorphisms in type 1 diabetes mellitus patients with autoimmune polyglandular syndrome type III.

Type 1 diabetes mellitus (T1D) is an organ-specific autoimmune disease characterized by T-cell mediated self-destruction of insulin-producing ß cells in the pancreas. T1D patients are prone to develop other glandular autoimmune disorders, such as autoimmune thyroid disease that occurs simultaneously with autoimmune polyglandular syndrome type III (APSIII). Signal transducer and activator of transcription 4 (STAT4) is a well-known regulator of proinflammatory cytokines, and interferon-induced with helicase C domain 1 (IFIH1) is activated in the interferon type I response. Both genes have been examined separately in autoimmune diseases and, in this study, we assessed their joint role in T1D and APSIII. We conducted a case-control study, enrolling 173 T1D patients and 191 healthy controls from northeastern Brazil, to assess the distribution of the rs7574865 and rs3024839 SNPs in STAT4 and the rs3747517 and rs1990760 SNPs in IFIH1 in T1D and APSIII patients. Additionally, we conducted a meta-analysis with the rs7574865 SNP in STAT4 (1392 T1D patients and 1629 controls) and the rs1990760 SNP in IFIH1 (25092 T1D patients and 28544 controls) to examine their association with T1D. Distribution of STAT4 and IFIH1 allelic frequencies did not show statistically significant differences between T1D patients and controls in our study population; however, the meta-analysis indicated that SNPs in STAT4 and IFIH1 are associated with T1D worldwide. Our findings indicate that although STAT4 and IFIH1 SNPs are not associated with T1D in a Brazilian population, they might play a role in susceptibility to T1D on a larger worldwide scale.

Vitamin D receptor (VDR) gene polymorphisms and susceptibility to systemic lupus erythematosus clinical manifestations.

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.