77 research outputs found
Candidate genes colocalized to linkage regions in inflammatory bowel disease
No full textBackground and Aims: The genes encoding for tumor necrosis factor-alpha (TNF-alpha), epidermal growth factor receptor (EGFR) and the vitamin D receptor (VDR) are colocalized to inflammatory bowel disease-associated linkage regions on chromosomes 6, 7 and 12. An association study of these gene polymorphisms with ulcerative colitis or Crohn's disease and a stratification according to disease phenotypes was performed in order to identify gentically homogenous subgroups. Patients and Methods: 119 healthy, unrelated controls, 95 patients with Crohn's disease and 93 patients with ulcerative colitis were genotyped for the (G to A) -308 TNF-alpha promoter polymorphism on chromosome 6, the codon 497 EGFR polymorphism on chromosome 7 and the Taql polymorphism of the VDR gene on chromosome 12. After genotyping, patients were stratified according to the respective disease phenotype. Results: A disequilibrium in the distribution of the VDR genotypes was found in patients with ulcerative colitis compared to controls (p = 0.024). In fistulizing and fibrostenotic Crohn's disease the `TT' genotype was significantly reduced compared with other phenotypes (p = 0.006), whereas the `tt' genotype was found more frequently (p = 0.04). The frequency of the WT allele of the EGFR gene was significantly higher in ulcerative colitis (p = 0.04) than in controls. Further significant differences, concerning the associations of the different polymorphisms and disease susceptibility or clinical phenotypes, were not observed. Conclusions: Regardless of the disease phenotype, the associations between the polymorphisms and inflammatory bowel disease investigated herein are modest, even after stratification for the disease phenotypes. Hence, these polymorphisms are unlikely to confer the reported linkage between inflammatory bowel disease and chromosomes 6, 7 and 12. Copyright (C) 2002 S. Karger AG, Basel
The human OCTN1 (SLC22A4) reconstituted in liposomes catalyzes acetylcholine transport which is defective in the mutant L503F associated to the Crohn's disease
No full textThe organic cation transporter (OCTN1) plays key roles in transport of selected organic cations, but understanding of its biological functions remains limited by restricted knowledge of its substrate targets. Here we show capacity of human OCTN1-reconstituted proteoliposomes to mediate uptake and efflux of [(3)H]acetylcholine, the Km of transport being 1.0mM with V(max) of 160nmol⋅mg(-1)protein⋅min(-1). OCTN1-mediated transport of this neurotransmitter was time-dependent and was stimulated by intraliposomal ATP. The transporter operates as uniporter but translocates acetylcholine in both directions. [(3)H]acetylcholine uptake was competitively inhibited by tetraethylammonium, γ-butyrobetaine and acetylcarnitine, and was also inhibited by various polyamines. Decreasing intraliposomal ATP concentrations increased OCTN Km for acetylcholine, but V(max) was unaffected. Evaluation of the acetylcholine transporter properties of a variant form of OCTN1, the Crohn's disease-associated 503F variant, revealed time course, Km and V(max) for acetylcholine uptake to be comparable to that of wild-type OCTN1. Km for acetylcholine efflux was also comparable for both OCTN1 species, but V(max) of OCTN1 503F-mediated acetylcholine efflux (1.9nmol⋅mg(-1)protein⋅min(-1)) was significantly lower than that of wild-type OCTN1 (14nmol⋅mg(-1)protein⋅min(-1)). These data identify a new transport role for OCTN1 and raise the possibility that its involvement in the non-neuronal acetylcholine system may be relevant to the pathogenesis of Crohn's disease
Gender-stratified analysis of DLG5 R30Q in 4707 patients with Crohn disease and 4973 controls from 12 Caucasian cohorts
No full textBackground: DLG5 p. R30Q has been reported to be associated with Crohn disease ( CD), but this association has not been replicated in most studies. A recent analysis of gender-stratified data from two case-control studies and two population cohorts found an association of DLG5 30Q with increased risk of CD in men but not in women and found differences between 30Q population frequencies for males and females. Male-female differences in population allele frequencies and male-specific risk could explain the difficulty in replicating the association with CD.
Methods: DLG5 R30Q genotype data were collected for patients with CD and controls from 11 studies that did not include gender-stratified allele counts in their published reports and tested for male-female frequency differences in controls and for case-control frequency differences in men and in women.
Results: The data showed no male-female allele frequency differences in controls. An exact conditional test gave marginal evidence that 30Q is associated with decreased risk of CD in women (p= 0.049, OR= 0.87, 95% CI 0.77 to 1.00). There was also a trend towards reduced 30Q frequencies in male patients with CD compared with male controls, but this was not significant at the 0.05 level (p = 0.058, OR= 0.87, 95% CI 0.74 to 1.01). When data from this study were combined with previously published, gender-stratified data, the 30Q allele was found to be associated with decreased risk of CD in women (p= 0.010, OR= 0.86, 95% CI 0.76 to 0.97), but not in men.
Conclusion: DLG5 30Q is associated with a small reduction in risk of CD in women
Geroderma osteodysplastica maps to a 4 Mb locus on chromosome 1q24
No full textImportant insights into the etiology of osteoporosis have been gained by the study of single gene disorders, including osteogenesis imperfecta. We report on the genetic mapping of geroderma osteodysplastica (GO), a rare autosomal recessive disorder of the connective tissue, characterized by wrinkly skin and severe osteoporosis. We undertook autozygosity mapping in one Libyan and four consanguineous Pakistani families with a total of 10 affected individuals to define a 4 Mb homozygous region on chromosome 1q24, which harbors the GO causative gene. No obvious candidate genes that encode known protein constituents of the extracellular matrix are found in the linked region. Importantly, our study demonstrates that GO is not allelic to wrinkly skin syndrome caused by mutations in ATP6V0A2. © 2008 Wiley-Liss, Inc
Classical HLA-DRB1 and DPB1 alleles account for HLA associations with primary biliary cirrhosis.
No full textNOD2/CARD15 gene mutation is not associated with susceptibility to Wegener's Granulomatosis
No full textNOD2/CARD15 gene mutation is not associated with susceptibility to Wegener's Granulomatosis
No full textNOD2/CARD15 gene mutation is not associated with susceptibility to Wegener's Granulomatosis
No full textNOD2/CARD15 gene mutation is not associated with susceptibility to Wegener's Granulomatosis
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