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J Satsangi

Publications and source records attributed to J Satsangi.

At least 55 records · Page 3Linked to original sources
PubMed2000

Exclusion of linkage of Crohn's disease to previously reported regions on chromosomes 12, 7, and 3 in the Belgian population indicates genetic heterogeneity.

Susceptibility to inflammatory bowel disease (IBD) is significantly determined by genetic factors. Linkage data from genome-wide searches have identified regions on chromosomes 16, 12, 7, and 3. Our goal was to replicate these four regions in a Belgian population of IBD families. Fifty-four IBD families were studied (47 with Crohn's disease [CD] and 7 with mixed CD and ulcerative colitis, containing 79 affected sibpairs (68 CD only, 11 mixed) for the regions previously implicated to chromosomes 16, 12, 7, and 3. In this study, no evidence for linkage was found on any of the four chromosomal regions studied for either the whole IBD dataset or the CD subgroup. The multipoint maximum logarithm of odds scores were less than 0.7 for all four regions. Exclusion mapping could significantly exclude chromosomes 3, 7, and 12. Despite earlier findings, we could significantly exclude linkage of CD with previously reported regions on chromosomes 12, 7, and 3, and could not find evidence for linkage to chromosome 16. It is important to report these findings in light of the genetic heterogeneity of IBD. A genome-wide search on a larger group of affected siblings is being analyzed to detect other possible susceptibility loci in the Belgian population.

Belgium↗
PubMed2000

Inflammatory bowel disease: progress toward a gene.

The pathogenesis of ulcerative colitis (UC) and Crohn's disease (CD) is still unknown, but the importance of genetic susceptibility has been clearly shown by epidemiological data from family and twin studies. Linkage studies have identified two susceptibility loci for inflammatory bowel disease (IBD) on chromosomes 12 and 16. Importantly, these linkages have been replicated by independent investigators, and studies of positional candidates within these regions continue, together with fine mapping strategies. Regions of 'suggestive' linkage on chromosomes 1, 3, 4, 6, 7, 10, 22 and X have also been reported in individual studies. Other important candidate genes investigated include the interleukin-1 receptor antagonist, MUC3 and genes of the human leukocyte antigen (HLA) system. The apparently conflicting data in different studies from around the world may be explained by ethnic differences, case mix and genetic heterogeneity. Replicated class II HLA associations include HLA DRB1*0103 and DR2 (DRB1*1502), involved in UC susceptibility, and HLA DRB1*03 and DR4 as resistance alleles for CD and UC respectively. Animal studies have provided insights from targeted mutations and quantitative trait locus analysis. The goals of continuing research include narrowing the regions of linkages and analysis of candidate genes, and possibly the application of newly developed methods using single nucleotide polymorphisms. Advances in IBD genetics hold the potential to provide knowledge about the disease pathogenesis at the molecular level, with ensuing benefits for clinical practice.

Animals↗
PubMed1999

Association of ulcerative colitis with rare VNTR alleles of the human intestinal mucin gene, MUC3.

Ulcerative colitis (UC), a common form of inflammatory bowel disease, is a multifactorial disorder with significant genetic influence. Recently, evidence of linkage on chromosome 7q near the intestinal mucin gene MUC3 was reported by an affected sib-pair analysis. Previous reports indicate a possible mucin abnormality in UC patients, but whether genetic differences in a specific mucin gene are associated with UC is unknown. Here we analysed polymorphisms of variable number of tandem repeats (VNTRs) within this gene using DNAs obtained from 243 Japanese (75 patients with UC and 168 controls), and to confirm the result we undertook a two-stage examination using 328 Caucasian samples (72 and 85 with UC in the first and second stages, respectively, and 171 controls). When the frequency of patients carrying one or two rare VNTR alleles was compared with that of controls, a significant increase was found first in Japanese patients (odds ratio 2.72, 95% CI 1.17-6.32, P = 0. 0308). In Caucasians, the odds ratio was 2.80 (95% CI 1.36-5.75, P = 0.0079) in the first stage, 2.43 (95% CI 1.20-4.92, P = 0.0196) in the second stage and 2.60 (95% CI 1.41-4.80, P = 0.0024) in total. The overall odds ratio was 2.64 (95% CI 1.60-4.33, P = 0.0001). This result suggests that rare alleles of the MUC3 gene may confer genetic predisposition to UC.

Alleles↗
PubMed1998

Genetics of inflammatory bowel disease.

1. The aetiology of the chronic inflammatory bowel diseases, Crohn's disease and ulcerative colitis, is uncertain. Studies of specific environmental factors and immune dysfunction have provided little insight into disease pathogenesis. 2. Concordance rates in twin pairs and siblings provide strong evidence that genetic factors are important in disease pathogenesis. In Oxford, information was obtained from 433 adult patients with Crohn's disease. Compared with the prevalence in the general population, the relative risks in siblings of patients with Crohn's disease calculated from these data were respectively 36.5 for Crohn's disease, 16.6 for ulcerative colitis and 24.7 for inflammatory bowel disease. 3. Clinical patterns of disease were compared in members of over 250 multiply affected families with inflammatory bowel disease. A high degree of concordance for many characteristics was noted (disease type, extent, extra-intestinal manifestations). However, in 77 affected parent-child pairs, the median age of onset in the parents was significantly higher than in offspring (P < 0.0001). These data reflect the results from other studies throughout the world, and are consistent with the phenomenon of genetic anticipation. 4. A detailed study investigating the contribution of the major histocompatibility complex was undertaken. Eighty-three affected sibling pairs were involved in a linkage analysis study; 348 patients with inflammatory bowel disease and 472 controls were involved in a detailed allelic association study. These data provide evidence that the major histocompatibility complex is an important determinant in ulcerative colitis, but not in Crohn's disease. 5. Cytokine genes are important candidate genes in inflammatory bowel disease. Allelic association study was performed to investigate the contribution of the gene encoding the interleukin-1 receptor antagonist and tumour necrosis factor-alpha. These data do not suggest that these genes encode important determinants of disease susceptibility in inflammatory bowel disease. 6. A two-stage genome-wide search for susceptibility loci in inflammatory bowel disease was performed involving 186 affected sibling pairs. The data provide strong evidence for the model of Crohn's disease and ulcerative colitis as related polygenic disorders. Loci on chromosomes 3, 7 and 12 were linked to inflammatory bowel disease overall, whereas loci on chromosomes 2 and 6 were linked only in ulcerative colitis. Linkage with chromosome 16 was noted in Crohn's disease only. Fine mapping of these susceptibility loci is in progress, and may lead to gene identification with attendant clinical benefits.

Age of Onset↗
PubMed1998

Contribution of the IL-2 and IL-10 genes to inflammatory bowel disease (IBD) susceptibility.

Although the importance of genetic susceptibility to IBD has been established by epidemiological studies, the genes involved remain poorly characterized. Important candidate genes include those encoding the immunoregulatory cytokines IL-2 and IL-10. The aim of this study was to assess the contribution of the IL-2 and IL-10 genes to IBD susceptibility. One hundred and ninety-eight pairs of siblings with IBD were genotyped at dinucleotide repeat polymorphisms within the IL-2 and IL-10 genes, and data analysed by the affected sib-pair method of linkage analysis and the transmission disequilibrium test (TDT). A subset of 89 affected sibling pairs was genotyped at markers flanking the IL-2 gene as part of a genome-wide search. The IL-2 polymorphism showed no linkage to IBD overall, but modest evidence for linkage to the ulcerative colitis (UC) data set (P = 0.028). A microsatellite 4 cM distal to the IL-2 gene showed a similar distortion in the ulcerative colitis subgroup (P = 0.006). The TDT showed some distortion of allelic transmission for the IL-2 polymorphism in the UC group, but this did not reach statistical significance (P = 0.09). Results for the IL-10 polymorphism were not significant. Thus the gene encoding IL-2 may contribute to UC susceptibility, but the effect is modest and must await replication in other data sets. The IL-10 gene does not appear to contribute to the risk of developing UC or Crohn's disease.

Alleles↗
PubMed1998

The presence of anti-neutrophil antibodies reflects clinical and genetic heterogeneity within inflammatory bowel disease.

A detailed investigation of the relationship between anti-neutrophil cytoplasmic antibodies (ANCA) status, HLA genotype, and clinical patterns of inflammatory bowel disease was carried out, involving 236 European patients resident in the United Kingdom [120 had ulcerative colitis (UC), 116 had Crohn's disease (CD)]. ANCA status was determined on coded plasma samples in Los Angeles using a two-stage assay [fixed neutrophil enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence], and HLA genotyping was carried out by polymerase chain reaction. The results provide evidence that ANCA reflect clinical and genetic heterogeneity within the inflammatory bowel diseases. In the UC patients, 78.3% were ANCA positive [64.2 perinuclear (pANCA)], but only 46.5% CD patients were ANCA positive (19.3% pANCA). Furthermore, mean ELISA binding was significantly lower in CD (14.5% +/- 18.8% versus 40.5% +/- 41.0% in UC, p = 2.31 x 10(-9)). Only 15 CD samples, all from patients with colonic disease, displayed ELISA > 20%; and the six CD patients with highest ELISA binding had clinical features very similar to ulcerative colitis. Moreover, in UC, significant relationships between ANCA status and genotype were noted. Thus, 92.7% of patients with the DR3 DQ2 TNF2 haplotype were ANCA positive [p = 0.03 versus DR3 DQ2 TNF2-negative patients (73.9%)]. ELISA binding was increased in DR3 DQ2 TNF2-positive patients (56.0 versus 35.7%, p = 0.02). In this population of UC, ANCA was not associated with DR2, DR4, or clinical pattern. These data emphasize the many factors that need to be considered in genetic marker studies in inflammatory bowel disease. Extensive disease heterogeneity, ethnicity, and methodological differences in ANCA detection are all pertinent.

Adult↗
PubMed1997

Mapping susceptibility loci in inflammatory bowel disease: why and how?

The cause of the inflammatory bowel diseases Crohn's disease and ulcerative colitis is unknown, but epidemiological evidence suggests that it is multifactorial with a strong genetic component. Several genetic loci probably contribute to disease susceptibility, accounting for the complex pattern of inheritance and heterogeneous clinical manifestations. The combination of candidate gene studies and, more recently, genome-wide searches has resulted in the identification of a number of putative susceptibility loci. With large-scale, fine-mapping studies under way, and accelerating progress in the physical mapping of the human genome, rapid progress is now being made towards the identification of the genes responsible for inflammatory bowel disease.

Animals↗
PubMed1997

Genetic markers may predict disease behavior in patients with ulcerative colitis.

BACKGROUND & AIMS: Recent studies have suggested that HLA DRB1*0103 and allele 2 of the interleukin 1 receptor antagonist (IL-1RA) gene predict severe and extensive ulcerative colitis, respectively. The aim of this study was to test these hypotheses in patients undergoing surgery for their colitis. METHODS: HLA DRB1 and DQB1 genotyping was performed in 99 patients and 472 controls. Genotyping for polymorphisms of genes encoding tumor necrosis factor alpha and IL-1RA was performed in 107 patients and 89 controls. Measurement of antineutrophil cytoplasmic antibody (ANCA) was performed in 72 patients and 58 healthy subjects by fixed neutrophil enzyme-linked immunosorbent assay and indirect immunofluorescence. RESULTS: The DRB1*0103 allele was increased in patients (14.1% vs. 3.2% in controls; P < 1 x 10[-5]). This association was greatest in patients with extensive disease (15.8%; P < 0.0001) or extraintestinal manifestations (22.8%; P < 0.0001): mouth ulcers (25.8%; P < 0.0001), arthritis (27.2%; P < 0.0001), and uveitis (35.7%; P < 0.0001). The DRB1*04 alleles were reduced in patients (P = 0.005). Differences were noted between extensive and distal disease in the frequency of allele 2 of IL-1RA (10.9% in distal vs. 28.6% in extensive; P = 0.01) and allele 2 homozygosity. ANCA was detected in 76.4% of patients. Carriage of IL-1RA allele 2 and tumor necrosis factor 2 allele was increased in ANCA-positive patients. CONCLUSIONS: Genetic markers may predict disease behavior in ulcerative colitis.

Adolescent↗
PubMed1996

Contribution of genes of the major histocompatibility complex to susceptibility and disease phenotype in inflammatory bowel disease.

BACKGROUND: Despite strong evidence implicating immune dysfunction and genetic predisposition in the pathogenesis of the chronic inflammatory bowel diseases Crohn's disease and ulcerative colitis, the importance of the genes of the major histocompatibility complex remains uncertain. We have investigated the contribution of HLA DRB1 and DQB genes by the strategies of non-parametric linkage analysis (affected sibling pair method) as well as association study. The relation between genotype and phenotype was examined in detail. METHODS: For linkage analysis 74 families in whom two or more siblings had inflammatory bowel disease were studied. A total of 83 affected sibling pairs were involved: in 42 pairs both siblings had Crohn's disease; in 29 both had ulcerative colitis; in 12 one sibling had Crohn's disease, the other ulcerative colitis. For the association study there were 175 patients with ulcerative colitis, 173 with Crohn's disease, and 472 controls. Details of sex, age of onset, disease extent, and family history were analysed. 24 patients with ulcerative colitis and 92 with Crohn's disease required surgery for refractory disease. HLA DRB1 and DQB1 gene-typing was performed by polymerase chain reaction with sequence-specific primers. FINDINGS: In ulcerative colitis, the sharing of alleles among affected sibling pairs provided evidence for linkage with DRB1 locus (p = 0.017, chi2 = 5.32). Of 29 affected sibling pairs studied, only one pair shared no DRB1 DQB haplotypes. 15 shared two DRB DQB haplotypes. In contrast, no linkage was noted for Crohn's disease (42 sibling pairs; p = 0.30, chi2 = 0.16) or for inflammatory bowel disease overall (83 sibling pairs, p = 0.16, chi2 = 2.28). In the association study the rare DRB1*103 (8.3% vs 3.2% in controls) and DRB1*12 (8.6% vs 2.1% in controls) alleles were associated with ulcerative colitis (p = 0.0074, chi2 = 7.22, odds ratio OR = 2.9 [95% CI 1.3-6.4] and p = 0.0056, chi2 = 12.63, OR = 4.33 [1.8-11.0] respectively). No association with alleles representing DR2 (p = 0.55, chi2 = 0.34) was noted. No overall association was seen in Crohn's disease. In ulcerative colitis, the frequency of DRB1*0301 DQB*0201 (DR3 DQ2) was reduced in females (9.8% vs 26.3% in controls, p = 0.037, chi2 = 8.39 OR = 0.34 [0.15-0.71]), particularly in those with distal disease (2.3%, p = 0.001 vs controls, chi2 = 11.35, OR = 0.07 [0.00-0.39]). In both males and females, the DR3 DQ2 haplotype was predictive of extensive ulcerative colitis (32.9% vs 10.7% in distal disease, p < 0.01, chi2 = 10.94, OR 4.09 [1.70-10.6]) but not of need for surgery (p = 0.93, chi2 = 0.01). INTERPRETATION: These data provide strong evidence for genetic heterogeneity in inflammatory bowel disease. Genes of the major histocompatibility complex are implicated as important inherited determinants of susceptibility to ulcerative colitis and may also influence the pattern of disease. In Crohn's disease, important susceptibility genes are likely to exist outside the HLA region.

Adult↗
PubMed1996

Two stage genome-wide search in inflammatory bowel disease provides evidence for susceptibility loci on chromosomes 3, 7 and 12.

Crohn's disease (CD) and ulcerative colitis (UC), the chronic inflammatory bowel diseases (CIBD), are common causes of gastro-intestinal disease in the Western world, with a combined prevalence of 100-200/100,000 (ref. 1). Epidemiological studies, particularly concordance rates in twin pairs and siblings, strongly implicate genetic susceptibility in the pathogenesis of CIBD. In fact, the relative contribution of genetic factors to the pathogenesis of CD may be greater than in schizophrenia, asthma or hypertension, and at least equivalent to that in insulin-dependent diabetes. Systematic screening of the entire human genome now provides a strategy for the identification of susceptibility genes in complex polygenic disorders. We undertook a two-stage genome search for susceptibility genes in inflammatory bowel disease involving 186 affected sibling pairs from 160 nuclear families. We provide strong evidence for the presence of susceptibility loci for both CD and UC on chromosome 3, 7 and 12. We obtained the highest lod score (5.47; P = 2.66 x 10(-7) with the marker D12S83 and lod scores of 3.08 and 2.69 for D7S669 and D3S1573, respectively. Our data suggest that CD and UC are closely related, but distinct, polygenic disorders that share some, but not all, susceptibility genes.

Chromosome Mapping↗
PubMed1996

Inflammatory bowel disease and the X chromosome.

A review of documented cases demonstrates a significant association of Turner's syndrome with Crohn's disease and ulcerative colitis; this association relates particularly to genetic constitutions comprising an abnormal rather than an absent X chromosome. The karyotype 46XiXq, in pure or mosaic form, appears to be a significant susceptibility factor for inflammatory bowel disease. This karyotype often gives rise to relatively weak phenotypic characteristics of Turner's syndrome, which may be overlooked in short females with inflammatory bowel disease. The association of inflammatory bowel disease with Turner's syndrome may reflect the presence on the X chromosome of genes involved in disease pathogenesis. Linkage analysis studies, involving microsatellite markers on the X chromosome, are being performed.

Adolescent↗
PubMed1996

Ulcerative colitis complicated by renal cell carcinoma: a series of three patients.

Three patients are described in whom renal cell carcinoma was diagnosed between seven months and 14 years after the onset of ulcerative colitis. All three had required treatment with corticosteroids and azathioprine, as well as maintenance therapy with 5-aminosalicylate derivatives, for chronic active colitis. One patient had coexisting polymyalgia rheumatica; one had primary biliary cirrhosis. It is uncertain whether this association, which has not previously been described, has pathogenetic importance or has arisen simply by chance. Genetic predisposition or the effect of drug treatment, particularly immunosuppression, may be pertinent to the co-occurrence of these diseases.

Carcinoma, Renal Cell↗
PubMed1996

Clinical patterns of familial inflammatory bowel disease.

BACKGROUND: Although many recent studies have shown the increased risk of inflammatory bowel disease in relatives of patients with Crohn's disease and ulcerative colitis, clinical patterns of disease within families remain relatively poorly documented. AIMS: In this study, clinical characteristics (disease type, extent, age on onset, need for surgery, and presence of extraintestinal manifestations) have been compared in affected subjects in multiply-affected families, with inflammatory bowel disease. METHODS: 54 families in whom one parent and at least one child were affected (a total of 77 parent-child pairs) and 155 families in whom at least two siblings were affected (a total of 190 affected sibling pairs) were involved. RESULTS: In affected parent-child pairs, parent and child were concordant for disease type in 58 of 77 pairs (75.3%), for extent in 63.6%, extraintestinal manifestations in 70.1%, and smoking history in 85%. The median age of onset in parents was significantly higher than offspring (p < 0.0001). In 40 pairs, 60.6%, the parent was at least 10 years older than child. Siblings were concordant for disease type in 81.6% of the affected sibling pairs, extent in 76.0%, extraintestinal manifestations in 83.8%, and smoking history in 81.3%. In contrast with the parent-child pairs, 68.1% (111 sibling pairs) siblings were diagnosed within 10 years of each other. The median age of onset was 24.0 years. CONCLUSIONS: This study has shown consistent clinical patterns in many families with inflammatory bowel disease. The differences in age of onset between parents and children are not readily explained by a simple cohort effect or ascertainment bias, and may reflect effects of genetic factors, producing anticipation between generations.

Age of Onset↗