Polymorphisms in the TLR6 gene associated with the inverse association between childhood acute lymphoblastic leukemia and atopic disease.

Little is known about the etiology of childhood acute lymphoblastic leukemia (ALL). The presence of atopic disease has been shown to protect against developing childhood ALL. The aim of this study was to examine whether single nucleotide polymorphisms (SNPs) in innate immunity genes previously associated with atopic disease, can elucidate the inverse association between childhood ALL and atopic disease. We studied 525 children, including 192 with childhood ALL, 149 with atopic disease and 184 healthy control subjects. We compared genotype distributions of 29 SNPs in genes of TLR2, TLR4, TLR6, TLR9, TLR10 and CD14 between the three groups and corrected for multiple testing. The genotype distributions of two SNPs in the TLR6 gene, rs5743798 and rs6531666, differed significantly between children with ALL, children with atopic disease and control subjects. Particularly in children with atopic eczema, risk alleles for atopic disease were observed more often than in control subjects, and less often in children with ALL than in control subjects. These findings support the immune surveillance hypothesis as an explanation for the protective association of atopic disease on childhood ALL. Further investigation is warranted to examine in more detail the role of innate immunity in the development of childhood ALL.

Association of polymorphisms in the TLR4 gene with the risk of developing neutropenia in children with leukemia.

Infections are a major cause of morbidity and mortality in children with acute lymphoblastic leukemia (ALL). Susceptibility to infections increases as the neutrophil count decreases. Despite identical treatment patients vary considerably in the number of neutropenic episodes. Toll-like receptor 4 (TLR4) has been shown to have a role in inhibiting apoptosis of neutrophils. Therefore, we hypothesized that polymorphisms in the TLR4 gene may influence the number of chemotherapy-induced neutropenic episodes. Eight single-nucleotide polymorphisms (SNPs) of the TLR4 gene were determined in 194 children aged 0-17 years, who were diagnosed with ALL. We compared the genotype distributions of the SNPs with the frequency of neutropenic episodes during treatment with chemotherapeutic regimens. The number of neutropenic episodes varied from 0 to 17, with a median of four neutropenic episodes. Four SNPs in the TLR4 gene (rs10759931, rs11536889, rs1927911 and rs6478317) were associated with an increased risk of developing chemotherapy-induced neutropenia, each sustaining correction for multiple testing. Further studies are required to elucidate whether pediatric patients with ALL with the particular SNPs in the TLR4 gene also experience more infections and would benefit from prophylactic antibiotic treatment, by a reduction of morbidity and mortality due to infections.

Association of the CLCA1 p.S357N variant with meconium ileus in European patients with cystic fibrosis.

In Cftr-/- mice that mostly die because of intestinal obstruction, intestinal expression of Clca3 is decreased, whereas upregulation of Clca3 results in amelioration of intestinal disease. The aim of the study was to investigate whether the p.S357N variant in CLCA1, the human orthologue of Clca3, acts as a modifier gene in a cohort of 682 European patients with cystic fibrosis (CF)-99 patients with meconium ileus. The 357SS genotype was significantly overrepresented in both patients with meconium ileus and also with a severe CFTR genotype (P = 0.009) and in p.F508del homozygotes (P = 0.002). This suggests that CLCA1 has similar important functions in CF-related intestinal obstruction in humans as in Cftr-/- mice.

Association of ATG16L1 and IRGM genes polymorphisms with inflammatory bowel disease: a meta-analysis approach.

The aim of this study was to determine the role of the ATG16L1 (rs2241880) and IRGM (rs13361189 and rs4958847) genes polymorphism in Crohn's disease (CD) and ulcerative colitis (UC). Our study included 557 CD and 425 UC patients and 672 ethnically matched Spanish controls and a meta-analysis with the data published to date. The polymorphisms were genotyped using predesigned TaqMan single nucleotide polymorphism genotyping assays. There was a statistically significant difference in the distribution of the ATG16L1 rs2241880 G allele between CD patients and controls in the Spanish population: P=6.5 x 10(-9), odds ratio (OR)=1.62. Although no differences were observed between UC patients and controls in the Spanish cohort, a meta-analysis demonstrated that the ATG16L1 G allele increase significantly risk for UC (P=0.0003, pooled OR=1.08). In addition, our meta-analysis data showed that IRGM rs13361189 and rs4958847 polymorphisms were associated with CD (rs13361189 C allele P=1.07 x 10(-19), pooled OR=1.34; rs4958847 A allele P=2.78 x 10(-17), pooled OR=1.31) and UC (rs13361189 P=0.0069, pooled OR=1.16; rs4958847 P=0.014, pooled OR=1.13). In conclusion, our results confirm the ATG16L1 rs2241880 and IRGM rs13361189 and rs4958847 polymorphisms as important markers for CD susceptibility and indicate that these variants are also associated with UC.

Heritability of serum iron, ferritin and transferrin saturation in a genetically isolated population, the Erasmus Rucphen Family (ERF) Study.

BACKGROUND: Iron has been implicated in the pathogenesis of various disorders. Mutations in the HFE gene are associated with an increase in serum iron parameters. The aim of this study was to estimate the heritability in serum iron parameters explained by HFE. METHODS: Ninety families (980 subjects) were included in the present analysis. Heritability estimation was conducted using the variance component method. The likelihood ratio test was used to compare models. Phenotypic and genetic correlations between serum iron parameters were calculated. RESULTS: The heritability (h(2) +/- SE) estimates were 0.23 +/- 0.07 (p < 0.0001) for iron, 0.29 +/- 0.09 (p < 0.0001) for ferritin and 0.28 +/- 0.07 (p < 0.0001) for transferrin saturation while adjusting for age, age(2) and sex. The HFE genotypes explained between 2 to 6% of the sex and age-adjusted variance in serum iron, ferritin and transferrin saturation. There was a high genetic correlation between serum iron parameters, suggesting pleiotropy between these traits. CONCLUSION: A substantial proportion of the variance of iron, ferritin and transferrin saturation can be explained by additive genetic effects, independent of sex and age. The HFE genotypes explained a considerable proportion of serum iron parameters and may be an important factor in the complex iron network.

Association of FAS (TNFRSF6)-670 gene polymorphism with villous atrophy in coeliac disease.

AIM: To investigate the association of FAS gene polymorphism with coeliac disease (CD) development. METHODS: FAS-G670A gene polymorphism, located in a gamma interferon activation site, was studied in 146 unrelated CD patients and 203 healthy ethnically matched controls. The restriction fragment length polymorphism (RFLP) method was used to identify FAS-G670A gene polymorphism. RESULTS: No significant difference was found in genotype frequency between CD cases and controls. In controls, however, the frequency of the GG genotype was significantly higher in women (26.5%) than in men (12.8%) (OR= 2.44, 95% CI 1.15-5.20, P=0.020) and it was also higher in men with CD than controls (OR=2.60, 95% CI 0.96-7.05, P=0.061). The GG genotype frequency was significantly higher in patients with most severe villous atrophy (Marsh IIIc lesions) (OR=3.74, 95% CI 1.19-11.82, P=0.025). A significantly less proportion of men suffered from Marsh IIIc lesions than women (OR=0.20, 95% CI 0.06-0.68, P=0.01). The risk of having severe villous atrophy increased with the additive effect of the G allele in women (P=0.027 for trend, age and gender adjusted). CONCLUSION: FAS-G670A gene polymorphism is associated with the severity of villous atrophy in CD. Female gender is also associated with the severity of villous atrophy.

Genetic and serological markers to identify phenotypic subgroups in a Dutch Crohn' s disease population.

BACKGROUND AND AIMS: Both genetic and microbial factors seem to play a pivotal role in the aetiopathogenesis of Crohn's disease. The CARD15 frameshift mutation might link host genetic factors and the indigenous microbial flora, since CARD15 expression is stimulated by peptidoglycan, thereby activating NF-kappaB. It is hypothesised that CARD15 mutation carriers have defective anti-microbial reactions, resulting in more penetrating lesions and antibody responses, which are now being used as highly specific markers for Crohn's disease. The serological marker anti-Saccharomyces cerevisiae antibody directed against cell wall oligomannosidic epitopes has high specificity for Crohn's disease. Perinuclear anti-neutrophil cytoplasmic antibodies have been found in a subgroup of Crohn's disease patients, mostly with colonic involvement. METHODS: We investigated the incidence of two CARD15 mutations (3020insC and 2722G>C), anti-S. cerevisiae antibody, and perinuclear anti-neutrophil cytoplasmic antibody in 108 (73F/35M) patients with Crohn's disease with a mean duration of disease since diagnosis of 16 (1-41) years in relation to their phenotype, according to the Vienna classification. RESULTS: The prevalence of CARD15 frameshift mutation was 21%. Of all patients, 62% were anti-S. cerevisiae antibody positive, and 9% had perinuclear anti-neutrophil cytoplasmic antibodies. The prevalence of both anti-S. cerevisiae antibodies and perinuclear anti-neutrophil cytoplasmic antibodies was higher in the mutation carriers compared to non-carriers. Remarkably, all patients with a CARD15 mutation and positive anti-S. cerevisiae antibody had ileal disease. Carriership of the mutation was significantly associated with penetrating behaviour of the disease and weakly associated with stricturing behaviour. Furthermore, anti-S. cerevisiae antibody was associated with ileal disease involvement. Finally, most perinuclear anti-neutrophil cytoplasmic antibody positive patients showed ulcerative-like behaviour of disease (by means of colonic localisation). CONCLUSIONS: Genetic and serologic markers might be useful in defining patient subgroups. This may result in a more accurate prediction of disease behaviour, prognosis and therapeutic approach.