Low levels of antibodies for the oral bacterium Tannerella forsythia predict cardiovascular disease mortality in men with myocardial infarction: A prospective cohort study.

Antibody levels to periodontal pathogens in prediction of cardiovascular disease (CVD) mortality were explored using data from a health survey in Oslo in 2000 (Oslo II-study) with 12 1/2 years follow-up. IgG antibodies to four common periodontal pathogens; Tannerella forsythia (TF), Porphyromonas gingivalis (PG), and Treponema denticola (TD) all termed collectively the "red complex", and Aggregatibacter actinomycetemcomitans(AA) were analysed. The study sample consisted of 1172 men drawn from a cohort of 6,530 men who participated in the Oslo II-study, where they provided information on medical and dental history. Of the study sample, 548 men had reported prior myocardial infarction (MI) at baseline whereas the remaining 624 men were randomly drawn from the ostensibly healthy participants for comparative analyses. Dental anamnestic information included tooth extractions and oral infections. An inverse relation was found for trend by the quartile risk level of TF predicting CVD mortality, p-value for trend = 0.017. Comparison of the first to fourth quartile of TF antibodies resulted in hazard ratio (HR) = 1.82, 95% confidence interval 1.12-2.94, p = 0.015, adjusted for age, education, diabetes, daily smoking, and systolic blood pressure. Specificity comparing decile 1 to deciles 2-10 of TF predicting mortality was 92.3%. We found an increased HR by low levels of antibodies to the bacterium T. forsythia predicting CVD mortality in a 12 ½ years follow-up in persons who had experienced an MI but not among non-MI men. This novel finding constitutes a plausible causal link between oral infections and CVD mortality.

Enterobius vermicularis and allergic conditions in Norwegian children.

Studies investigating the association between Enterobius vermicularis and allergic conditions have shown conflicting results. This study was conducted to test for any such associations in Norwegian children. Parents were asked to answer questionnaires concerning their children's history of allergies, wheezing or eczema and pinworm infections. Current pinworm infections were diagnosed by microscopic examination of anal scotch tape samples. The data were analysed using logistic regression. Atopic eczema, allergy or wheezing was reported to be confirmed by a physician in 23% of the children (84/364). A possible association between current pinworm infections and food allergy was found, with 17·5% of children without food allergy testing positive for pinworms, compared to 36·8% of children with food allergy (odds ratio 2·9, 95% confidence interval 1·1-8·0). No association was found between past pinworm treatments and present atopic conditions. The association between current E. vermicularis infections and food allergy warrants further study.

HLA-DRB1, -DQA1 and -DQB1 alleles and haplotypes in first-generation Pakistani immigrants in Norway.

Human leucocyte antigen (HLA) polymorphisms among immigrants from Pakistan have not been well investigated. Immigration to Norway started in the late 1960s for working purposes. From 1975, immigration was mainly for marriages and family reunion. When recruiting couples for a birth cohort study, we ended up with 65.5% of the 374 parents genotyped being closely related. This was also reflected in that 21% of newborns were homozygotes for their DRB1-DQA1-DQB1 genotype. For being able to study HLA class II genes frequencies among unrelated individuals, we had to exclude 195 of the parents from data analysis. High-resolution typing for the DRB1 locus, low/intermediate for the DQA1 locus and resolution genotyping for the DQB1 locus were performed in all the 179 parents and their newborns from the Punjab province of Pakistan. We identified 25 DRB1, nine DQA1 and 14 DRB1 alleles in the 179 unrelated parents included in our analysis. The most frequent alleles were DRB1*03:01:01 (15.9%) and DRB1*07:01:01 (15.9%), DQA1*01:03 (22.1%) and DQB1*02:01:01 (26.0%). Forty-one haplotypes were identified, including DRB1*13:02:01-DQA1*01:02-DQB1*06:03:01, not earlier reported. Supported by the few earlier reports on Pakistani groups living in Pakistan, it appears that alleles found among those living in Norway are of Indo-European or mixed ethnic origin. This study provides the first comprehensive report of HLA class II alleles and haplotypes in Norwegian Pakistani immigrants. When the unrelated parents were compared with all parents genotyped, there were, however, no significant differences in allele frequencies, confirming that consanguineous marriages are usual in Pakistan.

Genetic variants of the HLA-A, HLA-B and AIF1 loci show independent associations with type 1 diabetes in Norwegian families.

The main genetic predisposition to type 1 diabetes (T1D) is known to be conferred by the HLA-DRB1, -DQA1 and -DQB1 genes in the major histocompatibility complex (MHC). Other genetic factors within this complex are known to contribute, but their identity has often been controversial. This picture is shared with several other autoimmune diseases (AIDs). Moreover, as common genetic factors are known to exist between AIDs, associations reported with other AIDs may also be involved in T1D. In this study, we have used these observations in a candidate gene approach to look for additional MHC risk factors in T1D. Using complementary conditional methods (involving conditional logistic regression and family-based haplotype tests) and analyses of linkage disequilibrium (LD) patterns, we confirmed association for alleles of the HLA-A and HLA-B genes and found preliminary evidence for a novel association of a single-nucleotide polymorphism (rs2259571) in the AIF1 gene, independent of the DRB1-DQA1-DQB1 genes and of each other. However, no evidence of independent associations for a number of previously suggested candidate polymorphisms was detected. Our results illustrate the importance of a comprehensive adjustment for LD effects when performing association studies in this complex.

Joint effects of HLA, INS, PTPN22 and CTLA4 genes on the risk of type 1 diabetes.

BACKGROUND/HYPOTHESIS: HLA, INS, PTPN22 and CTLA4 are considered to be confirmed type 1 diabetes susceptibility genes. HLA, PTPN22 and CTLA4 are known to be involved in immune regulation. Few studies have systematically investigated the joint effect of multiple genetic variants. We evaluated joint effects of the four established genes on the risk of childhood-onset type 1 diabetes. METHODS: We genotyped 421 nuclear families, 1,331 patients and 1,625 controls for polymorphisms of HLA-DRB1, -DQA1 and -DQB1, the insulin gene (INS, -23 HphI), CTLA4 (JO27_1) and PTPN22 (Arg620Trp). RESULTS: The joint effect of HLA and PTPN22 on type 1 diabetes risk was significantly less than multiplicative in the case-control data, but a multiplicative model could not be rejected in the trio data. All other two-way gene-gene interactions fitted multiplicative models. The high-risk HLA genotype conferred a very high risk of type 1 diabetes (OR 20.6, using the neutral-risk HLA genotype as reference). When including also intermediate-risk HLA genotypes together with risk genotypes at the three non-HLA loci, the joint odds ratio was 61 (using non-risk genotypes at all loci as reference). CONCLUSION: Most established susceptibility genes seem to act approximately multiplicatively with other loci on the risk of disease except for the joint effect of HLA and PTPN22. The joint effect of multiple susceptibility loci conferred a very high risk of type 1 diabetes, but applies to a very small proportion of the general population. Using multiple susceptibility genotypes compared with HLA genotype alone seemed to influence the prediction of disease only marginally.

The FCRL3 -169T>C polymorphism is associated with rheumatoid arthritis and shows suggestive evidence of involvement with juvenile idiopathic arthritis in a Scandinavian panel of autoimmune diseases.

BACKGROUND AND OBJECTIVES: The Fc receptor-like 3 (FCRL3) gene -169T>C single nucleotide polymorphism (SNP) has been reported to be associated with several autoimmune diseases (AIDs) in Japanese populations. However, association results in other populations have been conflicting. Therefore, we investigated this SNP in a Scandinavian panel of AIDs. METHODS: We genotyped patients with rheumatoid arthritis (RA; n = 708), juvenile idiopathic arthritis (JIA; n = 524), systemic lupus erythaematosus (SLE; n = 166), ulcerative colitis (UC; n = 335), primary sclerosing cholangitis (PSC; n = 365), Crohn disease (CD; n = 149), a healthy control group (n = 1030) and 425 trio families with type 1 diabetes (T1D). Statistical analysis consisted of case-control and family-based association tests. RESULTS: RA was associated with the C allele (odds ratio (OR) = 1.16, 95% CI 1.01 to 1.33) and the CC genotype (OR = 1.30, 95% CI 1.01 to 1.67) of the FCRL3 -169T>C SNP in our material. Suggestive evidence for association was also found for JIA (CC genotype: OR = 1.30, 95% CI 0.99 to 1.70), and clinical subgroup analysis indicated that this was connected to the polyarticular subgroup. No significant association was found with SLE, UC, CD, PSC or T1D. In patients with RA, we found no significant interaction between the FCRL3 -169T>C and PTPN22 1858C>T SNPs, nor between the FCRL3 -169CC genotype and IgM-rheumatoid factor or anti-cyclic citrullinated peptide titre levels. CONCLUSION: We found an association between the FCRL3 -169T>C SNP and RA, and suggestive evidence for involvement with JIA, in a Norwegian population. These findings lend support for a role for this SNP in RA across ethnically diverse populations, and warrant follow-up studies in JIA.

Relative predispositional effects of HLA class II DRB1-DQB1 haplotypes and genotypes on type 1 diabetes: a meta-analysis.

The direct involvement of the human leukocyte antigen class II DR-DQ genes in type 1 diabetes (T1D) is well established, and these genes display a complex hierarchy of risk effects at the genotype and haplotype levels. We investigated, using data from 38 studies, whether the DR-DQ haplotypes and genotypes show the same relative predispositional effects across populations and ethnic groups. Significant differences in risk within a population were considered, as well as comparisons across populations using the patient/control (P/C) ratio. Within a population, the ratio of the P/C ratios for two different genotypes or haplotypes is a function only of the absolute penetrance values, allowing ranking of risk effects. Categories of consistent predisposing, intermediate ('neutral'), and protective haplotypes were identified and found to correlate with disease prevalence and the marked ethnic differences in DRB1-DQB1 frequencies. Specific effects were identified, for example for predisposing haplotypes, there was a statistically significant and consistent hierarchy for DR4 DQB1*0302s: DRB1*0405 =*0401 =*0402 > *0404 > *0403, with DRB1*0301 DQB1*0200 (DR3) being significantly less predisposing than DRB1*0402 and more than DRB1*0404. The predisposing DRB1*0401 DQB1*0302 haplotype was relatively increased compared with the protective haplotype DRB1*0401 DQB1*0301 in heterozygotes with DR3 compared with heterozygotes with DRB1*0101 DQB1*0501 (DR1). Our results show that meta-analyses and use of the P/C ratio and rankings thereof can be valuable in determining T1D risk factors at the haplotype and amino acid residue levels.

The relation between size at birth and risk of type 1 diabetes is not influenced by adjustment for the insulin gene (-23HphI) polymorphism or HLA-DQ genotype.

AIMS/HYPOTHESIS: Associations have been described between higher birthweight and increased risk of type 1 diabetes, and of insulin (INS) and human leucocyte antigen (HLA) genotypes that protect against diabetes with larger size at birth. We studied simultaneously the effects of size at birth, INS and HLA genotypes on the risk of type 1 diabetes to test whether the relation between size at birth and risk of type 1 diabetes would be strengthened after adjustment for INS and HLA genotypes. SUBJECTS AND METHODS: We designed a population-based case-control study in Norway with 471 cases of childhood-onset type 1 diabetes and 1,369 control subjects who were genotyped for the INS -23HphI polymorphism (surrogate for INS variable number of tandem repeats) and HLA-DQ alleles associated with type 1 diabetes. Data on birthweight and other perinatal factors were obtained from the Medical Birth Registry of Norway by record linkage. RESULTS: The data fitted a multiplicative model for the protective INS class III allele both within the INS locus and for the model with INS- and HLA-DQ-conferred risk of type 1 diabetes. We found no overall significant association between weight or head circumference at birth and the risk of type 1 diabetes, and adjustment for INS and HLA genotype did not influence this result. There was also no evidence for association of INS or HLA with size at birth among control subjects. CONCLUSIONS/INTERPRETATION: In contrast to suggestions from previous indirect studies, direct adjustment for INS and HLA genotypes did not lead to a stronger relation between birthweight and the risk of type 1 diabetes.

Longitudinal observation of enterovirus and adenovirus in stool samples from Norwegian infants with the highest genetic risk of type 1 diabetes.

BACKGROUND: Enterovirus and adenovirus are common in infancy, causing mostly asymptomatic infections. However, even an asymptomatic infection may be associated with increased risk of development of certain chronic non-infectious diseases, as has been suggested for enterovirus and type 1 diabetes. Data on occurrence and course of the infections in infancy are therefore important for designing effective approaches towards study of the association. OBJECTIVES: To estimate the frequency of enterovirus and adenovirus infections in Norwegian infants, to evaluate the duration of the infections, to investigate their association with symptoms, and to establish a robust procedure that will be used to study the association between these viruses and the development of auto-immunity leading to type 1 diabetes. STUDY DESIGN: Parents of infants, recruited for a study on environmental triggers of type 1 diabetes, submitted monthly samples of infant faeces, as well as information on symptoms of infection. The samples were analysed for enterovirus and adenovirus using quantitative real-time PCR, and enterovirus-positive samples were sequenced. RESULTS: Enteroviruses were found in 142/1,255 (11.3%), and adenoviruses in 138/1,255 (11.0%) of stool samples. Approximately half of the infants were exposed to these viruses at least once during the first year of observation (period 3-14 months of age). The presence of adenovirus was associated with fever and with symptoms of cold but not with diarrhoea and vomiting. The enterovirus positivity was not associated with any symptoms. CONCLUSIONS: The prevalence of enterovirus and adenovirus in longitudinally obtained faecal samples from infants is sufficiently high to enable studies of their association with chronic diseases. The present protocol for evaluating exposure to these viruses is well suited for large-scale efforts aimed at assessing possible long-term consequences, particularly in relation to type 1 diabetes.

Mapping of the bovine genes of the de novo AMP synthesis pathway.

Summary The purine nucleotides adenosine monophosphate (AMP) and guanosine monophosphate (GMP) are critical for energy metabolism, cell signalling and cell reproduction. Despite their essential function, little is known about the regulation and in vivo expression pattern of the genes involved in the de novo purine synthesis pathway. The complete coding region of the bovine phosphoribosylaminoimidazole carboxylase gene (PAICS), which catalyses steps 6 and 7 of the de novo purine biosynthesis pathway, as well as bovine genomic sequences of the six other genes in the pathway producing inosine monophosphate (IMP) and AMP [phosphoribosyl pyrophosphate amidotransferase (PPAT), phosphoribosylglycinamide formyltransferase (GART), phosphoribosylformylglycinamidine synthase (PFAS), adenylosuccinate lyase (ADSL), 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (ATIC) and adenylosuccinate synthase (ADSS)], were identified. The genes were mapped to segments of six different bovine chromosomes using a radiation hybrid (RH) cell panel. The gene PPAT, coding for the presumed rate-limiting enzyme of the purine de novo pathway was closely linked to PAICS on BTA6. These, and the other bovine locations i.e. GART at BTA1, PFAS at BTA19, ADSL at BTA5, ATIC at BTA2 and ADSS at BTA16, are in agreement with published comparative maps of cattle and man. PAICS and PPAT genes are known to be closely linked in human, rat and chicken. Previously, an expressed sequence fragment of PAICS (Bos taurus corpus luteum, BTCL9) was mapped to BTA13. By isolation and characterization of a BAC clone, we have now identified a PAICS processed pseudogene sequence (psiPAICS) on BTA13. Processed pseudogene sequences of PAICS and other genes of the purine biosynthesis pathway were identified in several mammalian species, indicating that the genes of this pathway have been susceptible to retrotransposition. The seven bovine genes are expressed at a higher level in testicular and ovary tissues compared with skeletal muscle.

Testing the possible negative association of type 1 diabetes and atopic disease by analysis of the interleukin 4 receptor gene.

Variations in the interleukin 4 receptor A (IL4RA) gene have been reported to be associated with atopy, asthma, and allergy, which may occur less frequently in subjects with type 1 diabetes (T1D). Since atopy shows a humoral immune reactivity pattern, and T1D results from a cellular (T lymphocyte) response, we hypothesised that alleles predisposing to atopy could be protective for T1D and transmitted less often than the expected 50% from heterozygous parents to offspring with T1D. We genotyped seven exonic single nucleotide polymorphisms (SNPs) and the -3223 C>T SNP in the putative promoter region of IL4RA in up to 3475 T1D families, including 1244 Finnish T1D families. Only the -3223 C>T SNP showed evidence of negative association (P=0.014). There was some evidence for an interaction between -3233 C>T and the T1D locus IDDM2 in the insulin gene region (P=0.001 in the combined and P=0.02 in the Finnish data set). We, therefore, cannot rule out a genetic effect of IL4RA in T1D, but it is not a major one.

Identification and physical mapping of genes expressed in the corpus luteum in cattle.

A representational difference analysis was performed to identify genes expressed in the corpus luteum of cattle. The corpus luteum is an ovarian structure that is essential for the establishment and maintenance of pregnancy. Knowledge of gene expression and function of corpus luteum will be important to improve fertility in humans and domestic animals. Housekeeping genes were removed from the corpus luteum representation (tester) using skeletal muscle as the subtracting agent (driver). A total of 80 clones of the final subtraction product were analysed by sequencing and 11 new bovine gene sequences were identified (pBTCL1-11). The sequences were mapped to segments of 10 different chromosomes using a somatic cell hybrid panel and a radiation hybrid panel. With one exception the locations are in agreement with published comparative maps of cattle and man. Expression in corpus luteum was verified by RT-PCR for all the 11 clones.

A genome scan for quantitative trait loci affecting milk production in Norwegian dairy cattle.

An autosomal genome scan for quantitative trait loci (QTL) affecting milk production traits was carried out on the Norwegian Dairy Cattle population. Six half-sibling families with a total of 285 sons organized according to a granddaughter design were analyzed by a multiple marker regression method. Suggestive QTL for one or several of the five milk traits (milk yield, protein percentage, protein yield, fat percentage and fat yield) were detected on chromosomes 3, 5, 6, 11, 13, 18 and 20. Among these results, the findings on chromosomes 3, 6, and 20 are highly supported by literature. The most convincing result was found close to marker FBN9 on chromosome 6, where a QTL was detected with alleles that cause a marked reduction in both protein and fat percentages and an increase in milk yield. The results for fat and protein percentage were highly significant even after accounting for multiple testing across the genome. Using bootstrapping, a 95% confidence interval for the position of the QTL for the percentage traits on chromosome 6 was estimated to 16 cM.

Correlations between the incidence of childhood-onset type I diabetes in Europe and HLA genotypes.

There are large variations in the incidence of Type I (insulin-dependent) diabetes mellitus within Europe, ranging from 3.2 cases per 100,000 person-years in the Republic of Macedonia to more than 40 new cases per 100,000 person-years in Finland. This variation could be caused by differences in the distribution of genetic susceptibility markers, by differences in the distribution of environmental disease determinants or by a combination of both. To assess how much genes contribute to this variation, we correlated the level of incidence of Type I diabetes with the prevalence in the general population of genetic susceptibility and protective markers encoded by the human leukocyte antigen (HLA)-DQ loci. Positive association was found for the combined group of genotypes associated with Type I diabetes risk (p < 0.001). The whole positive effect was, however, accounted for by the HLA-DQ2/ DQ8 (DQA1*0501-DQB1*0201/DQA1*0301-DQB1*0302) and HLA-DQ4/DQ8 (DQA1*0401-DQB1*0402/DQA*0301-DQB1*0302) genotypes (p < 0.001 and p < 0.004, respectively). No correlation was found between incidence of Type I diabetes and population prevalence of genotypes not encoding for aspartate on position 57 on the HLA-DQbeta chain. It was not possible to detect any negative correlation between Type I diabetes incidence and the prevalence of HLA-genotypes conferring protection against Type I diabetes in a population (HLA-DQA1*0102-DQB1*0602/X). The results suggest that a substantial part of the transnational variation in the incidence of childhood-onset Type I diabetes in Europe is explained by variations between populations in the distribution of particular DQ genotypes which confer a high risk of Type I diabetes in the general population.

Diabetes-associated HLA-DQ genes and birth weight.

An association has recently been described between increased birth weight and increased risk of childhood-onset type 1 diabetes. Whether this relationship is explained by genes associated with both increased birth weight and increased risk of type 1 diabetes is unknown. In the present study, we tested the association between birth weight and HLA-DQ genotypes known to confer risk for type 1 diabetes among 969 nondiabetic children randomly selected from the Norwegian population. We found that HLA genotypes previously shown to confer risk for type 1 diabetes were associated with reduced birth weight (the mean difference in birth weight between the DQB1*0602/DQB1*0602 and DQ8/DQ2 genotypes was 354 g [95% CI 105-604]), which was opposite of that expected if HLA genes explained the birth weight-type 1 diabetes association.

Suggestive evidence for association of human chromosome 18q12-q21 and its orthologue on rat and mouse chromosome 18 with several autoimmune diseases.

Some immune system disorders, such as type 1 diabetes, multiple sclerosis (MS), and rheumatoid arthritis (RA), share common features: the presence of autoantibodies and self-reactive T-cells, and a genetic association with the major histocompatibility complex. We have previously published evidence, from 1,708 families, for linkage and association of a haplotype of three markers in the D18S487 region of chromosome 18q21 with type 1 diabetes. Here, the three markers were typed in an independent set of 627 families and, although there was evidence for linkage (maximum logarithm of odds score [MLS] = 1.2; P = 0.02), no association was detected. Further linkage analysis revealed suggestive evidence for linkage of chromosome 18q21 to type 1 diabetes in 882 multiplex families (MLS = 2.2; lambdas = 1.2; P = 0.001), and by meta-analysis the orthologous region (also on chromosome 18) is linked to diabetes in rodents (P = 9 x 10(-4)). By meta-analysis, both human chromosome 18q12-q21 and the rodent orthologous region show positive evidence for linkage to an autoimmune phenotype (P = 0.004 and 2 x 10(-8), respectively, empirical P = 0.01 and 2 x 10(-4), respectively). In the diabetes-linked region of chromosome 18q12-q21, a candidate gene, deleted in colorectal carcinoma (DCC), was tested for association with human autoimmunity in 3,380 families with type 1 diabetes, MS, and RA. A haplotype ("2-10") of two newly characterized microsatellite markers within DCC showed evidence for association with autoimmunity (P = 5 x 10(-6)). Collectively, these data suggest that a locus (or loci) exists on human chromosome 18q12-q21 that influences multiple autoimmune diseases and that this association might be conserved between species.

Quantitative trait loci affecting clinical mastitis and somatic cell count in dairy cattle.

Norway has a field recording system for dairy cattle that includes recording of all veterinary treatments on an individual animal basis from 1978 onwards. Application of these data in a genome search for quantitative trait loci (QTL) verified genome-wise significant QTL affecting clinical mastitis on Chromosome (Chr) 6. Additional putative QTL for clinical mastitis were localized to Chrs. 3, 4, 14, and 27. The comprehensive field recording system includes information on somatic cell count as well. This trait is often used in selection against mastitis when direct information on clinical mastitis is not available. The absence of common QTL positions for the two traits in our study indicates that the use of somatic cell count data in QTL studies aimed for reducing the incidence of mastitis should be carefully evaluated.

HLA class II genetic association of type 1 diabetes mellitus in Czech children.

To examine human leukocyte antigen (HLA) class II association of type 1 diabetes mellitus (DM) in Czech children, we performed a case-control study of 261 patients diagnosed before the age of 15 and 289 non-diabetic control children. Complete HLA-DQA1, DQB1 genotyping and DRB1*04 subtyping were carried out by polymerase chain reactions with sequence-specific primers. The effect of the DRB1*04 subtypes was studied in DRB1*04 alleles carried on DQB1*0302-DQA1*03 haplotypes. The risk was statistically evaluated by testing 2 x 2 tables, considering corrected p-values < 0.05 significant. The DQB1*0302 (odds ratio, OR = 9.0), DQB1*0201 (OR = 3.4) and DQA1*03 (OR = 7.5) alleles were significantly associated with diabetes risk, while the DQB1*0602 (OR = 0.02), DQB1*0301 (OR = 0.08), DQB1*0503 (OR = 0.13), DQB1*0603 (OR = 0.20), DQA1*01 (OR = 0.28) and DQA1*02 (OR = 0.26) alleles were significantly protective. Of the DQA1-DQB1 genotypes, we point out the extremely high risk of OR = 116 conferred by HLA-DQA1*05-DQB1*0201/DQA1*03-DQB1*0302. Among DRB1*04 subtypes, DRB1*0403 was significantly protective (OR = 0.05, CI 95% 0.01-0.45). Since none of the remaining DRB1*04 subtypes was associated with type 1 DM, our study may present another piece of evidence that the DRB1*0401 and DRB1*0404 alleles do not modify type 1 diabetes risk generally in European populations.