Bernadett Faragó

Functional variants of interleukin-23 receptor gene confer risk for rheumatoid arthritis but not for systemic sclerosis

Objectives: Recently, an association was found between Crohn’s disease and the interleukin-23 receptor (IL-23R) gene. Since the IL-23/IL-17 pathway is known to associate with other autoimmune diseases, including rheumatoid arthritis (RA) and systemic sclerosis (SSc), we hypothesised that IL-23R could be a shared susceptibility gene. Methods: Groups of patients with rheumatoid arthritis (n = 412), systemic sclerosis (n = 224), Crohn’s disease (n = 190) and healthy controls (n = 220) were genotyped for rs10889677 (exon-3’UTR C2370A), rs2201841, and rs1884444 variants; the first two have been shown to confer risk for Crohn’s disease. Results: We observed an increased prevalence of the homozygous rs10889677 AA and homozygous rs2201841 CC genotypes both in the Crohn’s disease and in the RA groups as compared to the controls (12.1%, 11.9% vs 5.91%, p<0.05; and 13.2%, 13.1% vs 5.91%, p<0.05), but not in the SSc patients. Logistic regression analysis revealed that bearing these alleles represent risk for the development of rheumatoid arthritis (χ2 = 5.58, p = 0.018, OR = 2.15, 95% CI 1.14–4.06 for rs10889677; and χ2 = 7.45, p = 0.006, OR = 2.40, 95% CI 1.28–4.51 for rs2201841). The rs1884444 allele, which has been previously reported as neutral for development of Crohn’s disease, was also found neutral for all studied groups in the present study. Conclusions: The data reported here provide direct evidence that some allelic variants or haplogroups of IL-23R represent independent risk factors for rheumatoid arthritis as well as Crohn’s disease, but not for scleroderma.

Apolipoprotein A5 T-1131C Variant Confers Risk for Metabolic Syndrome

The −1131C is a naturally occurring variant of the apolipoprotein A5 (ApoA5) gene, which has been shown to associate with increased triglyceride levels. This variant has also been shown to confer risk for development of ischemic heart disease and stroke. The gene is in linkage disequilibrium with factors known to correlate with impaired glucose homeostasis. These observations prompted us to study the prevalence of the ApoA5 –1131C allele in patients with metabolic syndrome. A total of 201 metabolic syndrome patients and 210 controls were studied. In both groups the triglyceride levels of patients with −1131C allele were significantly increased compared to the subjects with −1131T allele (3.22 ±0.43 mmol/1 vs. 2.24 ±0.12 mmol/1, p<0.01 in the metabolic syndrome patients; 2.10 ±0.19 mmol/1 vs. 1.22 ±0.05 mmol/1, p<0.01 in the controls). In metabolic syndrome patients the prevalence of the ApoA5 –1131C variant was increased compared to the healthy controls (11% vs. 6.20%). Multiplex regression analysis model adjusted for age, gender, serum total cholesterol levels, acute myocardial infarction and stroke events revealed that the examined ApoA5 variant confers risk for the development of metabolic syndrome: the odds ratio at 95% confidence interval was 3.622 (1.200–10.936), p=0.02. Our findings strongly suggest that this variant is a risk factor for the development of hypertriglyceridemia and metabolic syndrome.

Coexistence of angiotensin II type-1 receptor A1166C and angiotensin-converting enzyme D/D polymorphism suggests susceptibility for small-vessel-associated ischemic stroke.

The renin-angiotensin system plays an important role in the maintenance of blood pressure homeostasis. The angiotensin-converting enzyme (ACE) converts angiotensin I into angiotensin II. Angiotensin II, which binds the angiotensin II type-1 receptor (AT1R), is a potent vasoconstrictor. On a pathophysiological basis, both ACE I/D and AT1R A1166C polymorphism lead to an enhanced activity of the angiotensin II-AT1R axis, thereby possibly contributing to circulatory disturbances. A mutually facilitatory effect may be presumed between the two polymorphisms. We examined whether this synergistic effect is involved in the evolution of different types of ischemic stroke. Genetic and clinical data on 308 consecutive patients with acutely developing ischemic stroke were analyzed. A total of 272 stroke and neuroimaging alteration-free subjects served as a control group. Univariate and logistic regression statistical approaches were used. The ACE D allele combined with the AT1R 1166C allele did not yield a risk of ischemic stroke. However, the co-occurrence of the homozygous ACE D/D and at least one AT1R 1166C allele was more frequent in the ischemic stroke group than in the control group (22.4 vs 11%, p<0.005, OR, 2.33; 95% CI, 1.46–3.7). After specific subgroup analysis, this synergistic association was even stronger for small-vessel ischemic stroke (OR, 3.44; 95% CI, 1.9–6.24; p<0.0005). Multivariate logistic regression analysis of the data confirmed this association (adjusted OR, 3.54, 95% CI, 1.88–7.16; p<0.0005). Our results demonstrate that ACE D/D and AT1R 1166C polymorphism were associated with the development of small-vessel ischemic stroke through a mutually facilitatory interplay between them. Genetic interactions might contribute to the altered functional network in renin-angiotensin system in vascular disorders.

Functional Variants of Glucokinase Regulatory Protein and Apolipoprotein A5 Genes in Ischemic Stroke

Both the natural variants of the apolipoprotein A5 (APOA5) and the glucokinase regulatory protein gene (GCKR) have been shown to associate with increased fasting triglyceride levels. Here, we investigated the possible association of the functional variants of these two genes with non-fasting triglyceride levels and their susceptibility nature in ischemic stroke. A total of 513 stroke patients and 172 healthy controls were genotyped. All the APOA5 variants (T-1131C, IVS3 + G476A, C56G, and T1259C) were associated with increased triglyceride levels in all stroke patients and controls; except for T1259C, they all conferred risk for the disease. No such association was found for the examined GCKR rs1260326 (C1337T) variant. Furthermore, we examined the effects of specific combinations of the GCKR rs1260326 and APOA5 polymorphisms. Our findings confirmed the previous results regarding the association of APOA5 variants with triglyceride-level increase and stroke susceptibility of these alleles. By contrast, we could not detect any association of the studied GCKR allele with triglyceride levels or with the susceptibility of stroke in the same cohort of patients. In addition, the effect of APOA5 did not change significantly when specific combinations of the two genes were present.

Prevalence of SLC22A4 1672T and SLC22A5 −207C combination defined TC haplotype in Hungarian ulcerative colitis patients

Ulcerative colitis (UC) is a chronic inflammatory disease of the gastrointestinal tract. The aim of this study was to verify the prevalence rate of the haplotype called TC, determined by combination of two functional alleles of OCTN cation transporter genes (SLC22A4 1672T and SLC22A5 /t-207C combination variants) in ulcerative colitis patients and unrelated healthy controls. The “TC haplotype” has recently been suggested to confer risk for UC. A total of 121 unrelated Hungarian subjects with UC and 110 matched controls were genotyped for the two single nucleotide polymorphisms. The genotypes were determined by using PCR/RFLP assay and direct sequencing. The SLC22A4 1672T allele frequency was 46.7% in the patients with UC and 46.4% in the controls, whereas the SLC22A5 −207C allele occurred in 48.8% of the patients and 51.4% of the controls. The prevalence of the TC haplotype was 19% in the patient group and 22.7% in controls. Since there was no accumulation of the TC haplotype in the patient group, our observation suggests that carrying the TC haplotype is not associated with a higher risk for UC in the Hungarian population.

The combination of homozygous MTHFR 677T and angiotensin II type-1 receptor 1166C variants confers the risk of small-vessel-associated ischemic stroke

Previous studies have suggested that both angiotensin II type-1 receptor (AT1R) 1166C and methylenetetrahydrofolate reductase (MTHFR) 677T variants can have disadvantageous effects on the small-vessel circulation under certain conditions. The purpose of this study was to analyze the possible consequences of the simultaneous distribution of these two genetic variants in different types of ischemic stroke. The genetic and clinical data on 357 ischemic stroke patients and 263 control subjects were analyzed by using univariate and logistic statistical approaches. Neither the MTHFR677T nor the AT1R 1166C genetic variant alone conferred the risk of any subtype of ischemic stroke. The combination of the homozygous MTHFR 677TT genotype and at least one AT1R 1166C allele occurred more frequently in the ischemic stroke patients (8.68%) than in the controls (4.56%, p<0.05). Specific subclassification of the patients revealed an accumulation of this combination in small-vessel-associated ischemic stroke (12.2%, p<0.01); multivariate logistic regression analysis of the data confirmed this association, with an odds ratio of 2.66 (95% confidence interval, 1.28–7.89; p<0.05). These findings suggest that the combination of these two genetic factors can contribute to the development of small-vessel cerebral infarcts. Although the exact mechanism of action is not known, addition of the unfavourable effects on the endothelial function can be presumed.

Galectin-2 3279TT variant protects against the lymphotoxin-α 252GG genotype associated ischaemic stroke

OBJECTIVE The galectin-2 protein is presumed to play a regulatory role in the intracellular trafficking of the lymphotoxin-alpha (LTA) cytokine. LTA is a pro-inflammatory factor, its 252GG homozygote variant is considered as a susceptibility factor for arteriosclerosis and cardiovascular diseases. By contrast, the galectin-2-encoding gene LGALS2 3279TT homozygote variant has been demonstrated to exert protection against myocardial infarction by reducing the transcriptional level of galectin-2, thereby leading to a reduced extracellular secretion of LTA. METHODS In the present study, we examined whether the LGALS2 3279TT homozygote variant alone can influence the prevalence of ischaemic stroke, and whether it can interact somehow with the disadvantageous LTA 252GG homozygote variant. Genetic and clinical data of 385 ischemic stroke patients and 303 stroke and neuroimaging alteration-free controls were analysed. RESULTS The combination of the LGALS2 3279TT and LTA 252GG homozygote was significantly less frequent in the ischemic stroke group (1.56%) than in the controls (5.94%, p<0.00187; overall stroke group: crude OR: 0.25, 95% CI: 0.1-0.64; adjusted OR: 0.03, 95% CI: 0.025-0.71). CONCLUSIONS This finding suggests a gene-gene interaction.

Cytotoxic T lymphocyte-associated antigen +49g variant confers risk for anti-CCP- and rheumatoid factor-positive type of rheumatoid arthritis only in combination with CT60* G allele

Controversial observations have been published on the association of the cytotoxic T lymphocyte associated antigen genes variants with rheumatoid arthritis (RA). After genotyping 428 patients and 230 matched controls, the prevalence of the CT60(∗)G allele was more frequent in RF- and/or anti-CCP-seropositive RApatients, compared to the healthy controls (P < .001). Regression analysis revealed that the CT60(∗)G allele is a possible predisposing factor for RA in these subgroups. No accumulation of the +49(∗)G allele was found among patients, and this variant was not found to correlate with RA. Assaying the possible genotype variations, the +49(∗)G-CT60(∗)G allelic combination was accumulated in seropositive RA-subtypes, and was associated with the risk of RA (OR = 1.73, P = .001 for the whole RA-population). Although the +49(∗)G allele did not mean a predisposition to RA alone, in combination with CT60(∗)G it, also conferred risk, suggesting that the +49A/G variant is associated with the risk of RA only in certain haplotypes.

The autosomal dominant cerebellar ataxias are hereditary neurodegenerative diseases

Even before a few decades ataxias were among the least understood neurological disorders but the clarification of their molecular background provides possibility for the accurate establishment of the diagnosis and gives a hand in the explanation of numerous extraordinary phenomena, like variable phenotypes in the same family. The cognition of the pathogenesis of spinocerebellar ataxias can grant a chance to the development of successful therapies instead of the present available merely symptomatic treatments. The rapid discovery of many genes and loci together with the segregation of ataxia subtypes can, however, cause inconvenience in the precise determination of the disorder. Our aim was to provide insight to the genetic background of these neurodegenerative diseases and also to give help in the correct diagnosis by the short description of the major ataxia subtypes.