| 1. |
|
|
| 2. |
- Hugot, J-P, et al.
(author)
-
Association of NOD2 leucine-rich repeat variants with susceptibility to Crohn's disease
- 2001
-
In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 411:6837, s. 599-603
-
Journal article (peer-reviewed)abstract
- Crohn's disease and ulcerative colitis, the two main types of chronic inflammatory bowel disease, are multifactorial conditions of unknown aetiology. A susceptibility locus for Crohn's disease has been mapped to chromosome 16. Here we have used a positional-cloning strategy, based on linkage analysis followed by linkage disequilibrium mapping, to identify three independent associations for Crohn's disease: a frameshift variant and two missense variants of NOD2, encoding a member of the Apaf-1/Ced-4 superfamily of apoptosis regulators that is expressed in monocytes. These NOD2 variants alter the structure of either the leucine-rich repeat domain of the protein or the adjacent region. NOD2 activates nuclear factor NF-?B, this activating function is regulated by the carboxy-terminal leucine-rich repeat domain, which has an inhibitory role and also acts as an intracellular receptor for components of microbial pathogens. These observations suggest that the NOD2 gene product confers susceptibility to Crohn's disease by altering the recognition of these components and/or by over-activating NF-?B in monocytes, thus documenting a molecular model for the pathogenic mechanism of Crohn's disease that can now be further investigated.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Hugot, JP, et al.
(author)
-
Clustering of Crohn's disease within affected sibships
- 2003
-
In: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 11:2, s. 179-184
-
Journal article (peer-reviewed)abstract
- Crohn's disease (CD) is a complex genetic disorder for which aetiology is unknown. Recently, genetic factors for susceptibility have been described. Several genetic loci have been mapped and partially explain the familial aggregations of the disease. However, environmental factors may also contribute to these aggregations. We considered that if the role of non-genetic factors was negligible, CD patients would be randomly distributed in sibships with multiple affected siblings. On the other hand if there was a significant environmental contribution, the siblings would be affected non-randomly over exposure status. In order to test this hypothesis, we studied 102 sibships with two or more affected siblings. A statistical test, named Cluster of Affected Sibling Test or CAST, was developed, based on the exact calculation of the probability of observing a given number of clusters of affected siblings in multiplex families. The null hypothesis of a random distribution of affected siblings was rejected (P=0,005). The observed excess of affected sibling clusters indicates that birth order influences the disease status. Considering that an adjacent order of birth is a global estimate of environmental sharing, this observation strongly suggests that environmental factors contribute to the observed familial aggregations of the disease. This observation provides evidence that familial CD is a relevant tool for further studies of environmental factors and gene-environment interaction. More generally, the CAST statistics may be widely applicable to estimate the involvement of environmental factors in the aetiology of other binary traits which may be observed in multiple members of the same sibship.
|
|
| 7. |
|
|
| 8. |
- Zouali, H, et al.
(author)
-
CARD4/NOD1 is not involved in inflammatory bowel disease
- 2003
-
In: Gut. - : BMJ. - 0017-5749 .- 1468-3288. ; 52:1, s. 71-74
-
Journal article (peer-reviewed)abstract
- Background and aims: Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are complex genetic disorders. CARD15/NOD2, a member of the Ced4 superfamily which includes Apaf-1 and CARD4/NOD1, has recently been associated with genetic predisposition to CD but additional genetic Factors remain to be identified. Because CARD4/NOD1 shares many structural and functional similarities with CARD15, we tested its putative role in IBD. Patients and methods: The 11 exons of CARD4 were screened for the presence of variants in 63 unrelated IBD patients. The only non-private genetic variation encoding for a substitution in the peptidic chain was genotyped in 381 IBD families (235 CD, 58 UC, 81 mixed, and seven indeterminate colitis families) using a polymerase chain reaction-restriction fragment length polymorphism procedure. Genotyping data were analysed by the transmission disequilibrium test. Results: Five of nine sequence variations identified in the coding sequence of the gene encoded for non-conservative changes (E266K, D372N, R705Q, T787M, and T787K). Four were present in only one family. The remaining variant (E266K), which exhibited an allele frequency of 0.28, was not associated with CD, UC, or IBD. Furthermore, IBD patients carrying sequence variations in their CARD4 gene had a similar phenotype to those with a normal sequence. Conclusion: Our results suggest that CARD4 does not play a major role in genetic susceptibility to IBD.
|
|
| 9. |
- Zouali, H, et al.
(author)
-
Genetic refinement and physical mapping of a chromosome 16q candidate region for inflammatory bowel disease
- 2001
-
In: European Journal of Human Genetics. - : Springer Science and Business Media LLC. - 1018-4813 .- 1476-5438. ; 9:10, s. 731-742
-
Journal article (peer-reviewed)abstract
- Crohn's disease (CD) is a complex genetic disorder for which a susceptibility gene, IBD1, has been mapped within the pericentromeric region of chromosome 16. In order to refine the location of IBD1, 77 multiplex CD families were genotyped for 26 microsatellite markers evenly spaced by approximately 1 cM. Nonparametric linkage analyses exhibited a maximum NPL score of 3.49 (P=2.37 ╫ 10-4) in a region centred by markers D16S3136, D16S3117 and D16S770. Simulation studies showed that the probability for IBD1 to be located in a 5 cM region around these markers was 70%. A 2.5 Mb YAC and BAC contig map spanning this genetic region on chromosome band 16q12 was built. TDT analyses demonstrated suggestive association between the 207 bp allele of D16S3136 (P<0.05) and a new biallellic marker hb27g11f-end (P=0.01). These markers were located in the hb27g11 and hb87b10 BAC clones from the contig. Taken together, the present results provide a crucial preliminary step before an exhaustive linkage disequilibrium mapping of putatively transcribed regions to identify IBD1.
|
|
| 10. |
|
|
| 11. |
- Margaritte-Jeannin, P, et al.
(author)
-
HLA-DQ relative risks for coeliac disease in European populations: a study of the European Genetics Cluster on Coeliac Disease.
- 2004
-
In: Tissue antigens. - : Wiley. - 0001-2815 .- 1399-0039. ; 63:6, s. 562-7
-
Journal article (peer-reviewed)abstract
- Coeliac disease is an enteropathy due to an intolerance to gluten. The association between HLA-DQ genes and CD is well established. The majority of patients carry the HLA-DQ heterodimer encoded by DQA1*05/DQB1*02, either in cis or in trans. The remaining patients carry either part of the DQ heterodimer or DQA1*03-DQB1*0302. The aim of the study was to estimate the risks associated with different DQ genotypes in European populations. HLA information was available for 470 trio families from four countries: France (117), Italy (128), and Norway and Sweden (225). Five DQA1-DQB1 haplotypes were considered and control haplotype frequencies were estimated from the set of parental haplotypes not transmitted to the affected child. The possible genotypes were grouped into five genotype groups, based on the hierarchy of risk reported in the literature. A north-south gradient in the genotype group frequencies is observed in probands: homogeneity is strongly rejected between all country pairs. For each country, the relative risks associated with each genotype group were computed taking into account the control haplotype frequencies. Homogeneity of relative risks between countries was tested pairwise by maximum likelihood ratio statistics. The hypothesis of homogeneity of relative risks is rejected (P is approximately 10(-6)) for all country pairs. In conclusion, the gradient in the genotype group frequencies in probands is not only due to differences in haplotype frequencies but also due to differences in genotype relative risks in the studied populations; the relative risks associated with each DQ genotype group are different between northern and southern European countries; neither are they ordered in the same way.
|
|
