We densely genotyped, using 1000 Genomes Project pilot CEU and additional re-sequencing study variants, 183 reported immune-mediated disease non-HLA risk loci in 12,041 celiac disease cases and 12,228 controls. We identified 13 new celiac disease risk loci at genome wide significance, bringing the total number of known loci (including HLA) to 40. Multiple independent association signals are found at over a third of these loci, attributable to a combination of common, low frequency, and rare genetic variants. In comparison with previously available data such as HapMap3, our dense genotyping in a large sample size provided increased resolution of the pattern of linkage disequilibrium, and suggested localization of many signals to finer scale regions. In particular, 29 of 54 fine-mapped signals appeared localized to specific single genes - and in some instances to gene regulatory elements. We define a complex genetic architecture of risk regions, and refine risk signals, providing a next step towards elucidating causal disease mechanisms.

Recent genetic studies have revealed shared immunological mechanisms in several immune-related disorders that further our understanding of the development and concomitance of these diseases. Our Review focuses on these shared aspects, using the novel findings of recently performed genome-wide association studies and non-synonymous SNP scans as a starting point. We discuss how identifying new genes that are associated with more than one autoimmune or chronic inflammatory disorder could explain the genetic basis of the shared pathogenesis of immune-related diseases. This analysis helps to highlight the key molecular pathways that are involved in these disorders and the potential roles of novel genes in immune-related diseases.

Candida albicans is the most common human fungal pathogen causing mucosal and systemic infections. However, human antifungal immunity remains poorly defined. Here, by integrating transcriptional analysis and functional genomics, we identified Candida-specific host defense mechanisms in humans. Candida induced significant expression of genes from the type I interferon (IFN) pathway in human peripheral blood mononuclear cells. This unexpectedly prominent role of type I IFN pathway in anti-Candida host defense was supported by additional evidence. Polymorphisms in type I IFN genes modulated Candida-induced cytokine production and were correlated with susceptibility to systemic candidiasis. In in-vitro experiments, type I IFNs skewed Candida-induced inflammation from a Th17-response toward a Th1-response. Patients with chronic mucocutaneaous candidiasis displayed defective expression of genes in the type I IFN pathway. These findings indicate that the type I IFN pathway is a main signature of Candida-induced inflammation and plays a crucial role in anti-Candida host defense in humans.

The two main phenotypes of inflammatory bowel disease (IBD)--Crohn's disease (CD) and ulcerative colitis (UC)--are chronic intestinal inflammatory disorders with a complex genetic background. Using a three-stage design, we performed a functional candidate-gene analysis of innate immune pathway in IBD. In phase I, we typed 354 SNPs from 85 innate immunity genes in 520 Dutch IBD patients (284 CD, 236 UC) and 808 controls. In phase II, ten autosomal SNPs showing association at p < 0.006 in phase I were replicated in a second cohort of 545 IBD patients (326 CD, 219 UC) and 360 controls. In phase III, four SNPs with p < 0.01 in the combined phase I and phase II analysis were genotyped in an additional 786 IBD samples (452 CD, 334 UC) and 768 independent controls. Joint analysis of 1851 IBD patients (1062 CD, 789 UC) and 1936 controls demonstrated strong association to the IL18RAP rs917997 SNP for both CD and UC (p(IBD) 1.9 x 10(-8); OR 1.35). Association in CD is independently supported by the Crohn's disease dataset of the Wellcome Trust Case Control Consortium (imputed SNP rs917997, p = 9.19 x 10(-4)). In addition, an association of the CARD9 rs10870077 SNP to CD and UC was observed (p(IBD) = 3.25 x 10(-5); OR 1.21). Both genes are located in extended haplotype blocks on 2q11-2q12 and 9q34.3, respectively. Our results indicate two IBD loci and further support the importance of the innate immune system in the predisposition to both CD and UC.

EU and the Seventh Framework Programme (the MeDALL project).

Rationale: Asthma is a chronic inflammatory airway disease that affects more than 300 million individuals worldwide. Asthma is caused by interaction of genetic and environmental factors. Bronchial hyperresponsiveness (BHR) is a hallmark of asthma and results from increased sensitivity of the airways to physical or chemical stimulants. BHR and asthma are linked to chromosome 5q31-q33. Objectives: To identify a gene for BHR on chromosome 5q31-q33. Methods: In 200 Dutch families with asthma, linkage analysis and fine mapping were performed, and the Protocadherin 1 gene (PCDH1) was identified. PCDH1 was resequenced in 96 subjects from ethnically diverse populations to identify novel sequence variants. Subsequent replication studies were undertaken in seven populations from The Netherlands, the United Kingdom, and the United States, including two general population samples, two family samples, and three case-control samples. PCDH1 mRNA and protein expression was investigated using polymerase chain reaction, Western blotting, and immunohistochemistry. Measurements and Main Results: In seven out of eight populations (n 5 6,168) from The Netherlands, United Kingdom, and United States, PCHD1 gene variants were significantly associated with BHR (P values, 0.005-0.05) This association was present in both families with asthma and general populations. PCDH1 mRNA and protein were expressed in airway epithelial cells and in macrophages. Conclusions: PCDH1 is a novel gene for BHR in adults and children. The identification of PCDH1 as a BHR susceptibility gene may suggest that a structural defect in the integrity of the airway epithelium, the first line of defense against inhaled substances, contributes to the development of BHR.

Rapid targeted genomics combined with copy number variant detection adds important value in the neonatal and pediatric intensive care setting. It led to a fast diagnosis in 30% of critically ill children for whom the routine clinical workup was unsuccessful.

BackgroundThe majority of coeliac disease (CD) patients are not being properly diagnosed and therefore remain untreated, leading to a greater risk of developing CD-associated complications. The major genetic risk heterodimer, HLA-DQ2 and DQ8, is already used clinically to help exclude disease. However, approximately 40% of the population carry these alleles and the majority never develop CD.ObjectiveWe explored whether CD risk prediction can be improved by adding non-HLA-susceptible variants to common HLA testing.DesignWe developed an average weighted genetic risk score with 10, 26 and 57 single nucleotide polymorphisms (SNP) in 2675 cases and 2815 controls and assessed the improvement in risk prediction provided by the non-HLA SNP. Moreover, we assessed the transferability of the genetic risk model with 26 non-HLA variants to a nested case–control population (n=1709) and a prospective cohort (n=1245) and then tested how well this model predicted CD outcome for 985 independent individuals.ResultsAdding 57 non-HLA variants to HLA testing showed a statistically significant improvement compared to scores from models based on HLA only, HLA plus 10 SNP and HLA plus 26 SNP. With 57 non-HLA variants, the area under the receiver operator characteristic curve reached 0.854 compared to 0.823 for HLA only, and 11.1% of individuals were reclassified to a more accurate risk group. We show that the risk model with HLA plus 26 SNP is useful in independent populations.ConclusionsPredicting risk with 57 additional non-HLA variants improved the identification of potential CD patients. This demonstrates a possible role for combined HLA and non-HLA genetic testing in diagnostic work for CD.