Graves' disease (GD) is an autoimmune thyroid disease. Multiple genetic factors are believed to be involved in its pathogenesis, but the factors are largely unknown, except for sex (female disease preponderance) and the role of human leukocyte antigen (HLA) genes on chromosome 6. To understand the mechanisms underlying the development of GD, a search for non-HLA-linked genes is crucial, and we tested several candidate genes, including the CTLA-4 gene on chromosome 2q33. CTLA-4 molecules may either facilitate or down-regulate the second signal to T-cells, which is provided by the interaction between the two accessory molecules CD28 and B7. One hundred and thirty-three Caucasian patients (26 males) with GD and 85 local controls were included in this study. Polymerase chain reaction was used to amplify DNA containing the (AT)n repeat within the 3'-untranslated region of exon 3 of the CTLA-4 gene. The 5'-forward primer was radiolabeled, and amplified products were resolved on 5-7% sequencing gels. All subjects were previously typed for HLA class II alleles. Twenty-one alleles were observed with sizes ranging from 88-134 basepairs. In the association analysis, the genotype frequencies between GD patients and controls differed significantly (P = 0.012), and the difference was attributable to a higher frequency of the 106-basepair allele among patients (relative risk, 2.82). When the patients were subdivided with respect to sex and HLA, the phenotype frequencies of allele 106 was higher in the female patients with protective HLA specificities (DQA1*0201 positive/DQA1*0501 negative) than in those with susceptible HLA specificities (DQA1*0201 negative/DQA1*0501 positive; 81.8% vs. 45.5%; P = 0.026). The CTLA-4 gene or a closely associated gene (including CD28) confers susceptibility to GD. This association may be more important in female patients with protective HLA specificities, who otherwise would be at low risk of developing the disease.

Susceptibility to Graves' disease (GD) is determined by environmental and genetic factors. The genetic susceptibility to GD is conferred by genes in the human leukocyte antigen (HLA), and several other genes unlinked to HLA are thought to contribute to the development of GD. Three recent papers described the association of GD with the CTLA-4 gene. CTLA-4 is a candidate gene for T-cell mediated autoimmune diseases because it is a negative regulator of T-cell proliferation. As CTLA-4 association with GD may be influenced by the racial composition of the population, it is important to study it in other ethnic groups. We investigated the distribution of CTLA-4 gene polymorphism in 153 Japanese patients with GD (35 males and 118 females) and 200 controls (96 males and 104 females). An A/G transition at position 49 of exon 1 was analyzed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The distribution of genotype frequencies differs between GD and controls (chi2 = 9.46, 2 degrees of freedom, p < 0.01). The presence of at least one G allele (GG or AG) conferred an odds ratio of 2.64 (95% CI = 1.92-3.36). The present study supported the association of the CTLA-4 gene with GD in Japanese and showed that the CTLA4 gene could be one of the non-HLA linked susceptibility genes for GD.

Genetic variations in cytochrome P450 2C9 (CYP2C9) are known to contribute to interindividual and interethnic variability in response to clinical drugs such as warfarin. In the present study, CYP2C9 from 263 Japanese subjects was resequenced, resulting in the discovery of 62 variations including 32 novel ones. In addition to the two known non-synonymous single nucleotide polymorphisms (SNPs), Ile359Leu (*3; allele frequency=0.030) and Leu90Pro (*13; 0.002), seven novel non-synonymous SNPs, Leu17Ile (0.002), Lys118ArgfsX9 (*25; 0.002), Thr130Arg (*26; 0.002), Arg150Leu (*27; 0.004), Gln214Leu (*28; 0.002), Pro279Thr (*29; 0.002) and Ala477Thr (*30; 0.002), were found. Functional characterization of novel alleles using a mammalian cell expression system in vitro revealed that *25 was a null allele and that *26, *28 and *30 were defective alleles. The *26 product showed a 90% decrease in the Vmax value but little change in the Km value towards diclofenac. Both *28 and *30 products showed two-fold higher Km values and three-fold lower Vmax values than the *1 allele, suggesting the importance of Gln214 and Ala477 for substrate recognition. Linkage disequilibrium and haplotype analyses were performed using the detected variations. Only five haplotypes (frequency >0.02) accounted for most (>87%) of the inferred haplotypes, and they were closely associated with the haplotypes of CYP2C19 in Japanese. Although the haplotype structure of CYP2C9 was rather simple in Japanese, the haplotype distribution was quite different from those previously reported in Caucasians and Africans. Taken together, novel defective alleles and detailed haplotype structures would be useful for determining metabolic phenotypes of CYP2C9 substrate drugs in Japanese and probably Asians.

Graves' disease (GD) is an autoimmune disease of the thyroid gland. Genes of, or closely associated to, the HLA complex are assumed to contribute to the genetic predisposition to GD. We have previously reported an increased frequency of HLA-DR3/DQ2 in Caucasian patients with GD, and recently the importance of Dw24 encoded by DRB3 gene has been suggested. To further investigate the associations of GD and these genes, 94 unrelated patients with GD and 75 control subjects were typed for HLA-DRB3, -DRB1, -DQA1, and -DQB1, using sequence-specific oligonucleotide probes to analyze polymerase chain reaction amplified DNA (PCR-SSO). Three findings emerged from these studies. 1) The frequency of subjects positive for DQA1*0501 (GD, 73.4% vs. control 42.7%, P = 0.0001, Pc < 0.001, RR = 3.71) was significantly increased among patients. The frequency of DR3 (GD, 34.0% vs. control 17.3%, P = 0.0146, RR = 2.46), which is in tight linkage disequilibrium with DQA1*0501, was also increased; however, it was not significant when the P value was corrected for the number of antigens tested. Neither DQB1 nor DRB3 alleles were significantly increased in frequency. 2) After exclusion of DR3-positive subjects, DQA1*0501 was still significantly increased (GD, 59.7% vs. control 30.6%, P = 0.0012, Pc < 0.01, RR = 3.35) among patients. 3) The distributions of Dw24 and Dw25,26 (Dw25 or Dw26) did not differ between patients and controls on either DR3 positive or negative groups. These findings suggest that DQA1*0501, or a closely associated unknown gene, confers susceptibility to GD, while Dw24 is not directly involved. The importance of DR3, however, remains to be elucidated, because of the fixed linkage with DQA1*0501.

Graves' disease (GD) is an autoimmune thyroid disease. Multiple genetic factors are believed to be involved in its pathogenesis, but the factors are largely unknown, except for sex (female disease preponderance) and the role of human leukocyte antigen (HLA) genes on chromosome 6. To understand the mechanisms underlying the development of GD, a search for non-HLA-linked genes is crucial, and we tested several candidate genes, including the CTLA-4 gene on chromosome 2q33. CTLA-4 molecules may either facilitate or down-regulate the second signal to T-cells, which is provided by the interaction between the two accessory molecules CD28 and B7. One hundred and thirty-three Caucasian patients (26 males) with GD and 85 local controls were included in this study. Polymerase chain reaction was used to amplify DNA containing the (AT)n repeat within the 3'-untranslated region of exon 3 of the CTLA-4 gene. The 5'-forward primer was radiolabeled, and amplified products were resolved on 5-7% sequencing gels. All subjects were previously typed for HLA class II alleles. Twenty-one alleles were observed with sizes ranging from 88-134 basepairs. In the association analysis, the genotype frequencies between GD patients and controls differed significantly (P = 0.012), and the difference was attributable to a higher frequency of the 106-basepair allele among patients (relative risk, 2.82). When the patients were subdivided with respect to sex and HLA, the phenotype frequencies of allele 106 was higher in the female patients with protective HLA specificities (DQA1*0201 positive/DQA1*0501 negative) than in those with susceptible HLA specificities (DQA1*0201 negative/DQA1*0501 positive; 81.8% vs. 45.5%; P = 0.026). The CTLA-4 gene or a closely associated gene (including CD28) confers susceptibility to GD. This association may be more important in female patients with protective HLA specificities, who otherwise would be at low risk of developing the disease.

Type 1 diabetes mellitus is recognized as a T-cell-mediated autoimmune disease. Vitamin D compounds are known to suppress T-cell activation by binding to the vitamin D receptor (VDR); and thus, VDR gene polymorphisms may be related to T-cell-mediated autoimmune diseases. We, therefore, investigated a VDR gene polymorphism in type 1 diabetes. We examined the VDR gene Bsm I polymorphism in 203 type 1 diabetic patients and 222 controls, and the association between the VDR gene polymorphism and type 1 diabetes and their onset pattern. We found a significantly higher frequency of B allele in type 1 diabetics overall, compared with controls (P = 0.0010). Moreover, there was a significant difference in B-allele frequency between acute-onset type 1 diabetics and controls (P = 0.0002), whereas this difference was not observed between slow-onset type 1 diabetics and controls. Regardless of the existence of islet-associated autoantibody, we found a significant difference in B-allele frequency between acute-onset type 1 diabetics and controls. In conclusion, we found an association between a VDR gene polymorphism and acute-onset type 1 diabetes. Assessment of this VDR gene polymorphism may contribute to prediction of the onset pattern in individuals with a high risk of type 1 diabetes.

Background: Vitamin D has been shown to exert manifold immunomodulatory effects. Type 1 diabetes mellitus (T1DM) is regarded to be immune-mediated and vitamin D prevents the development of diabetes in the NOD mouse. We studied the association between T1DM and the initiation codon polymorphism in exon 2 of the vitamin D receptor gene in a Japanese population. We also investigated associations between the vitamin D receptor polymorphism and GAD65-antibody (Ab) positivity. We carried out polymerase chain reaction-restriction fragment length polymorphism analysis in 110 Japanese T1DM patients and 250 control subjects. GAD65 antibodies were assessed in 78 patients with T1DM.

Forty-eight single nucleotide variations, including 27 novel ones, were found in the 5'- regulatory region, all of the exons and their surrounding introns of CYP2C19 in 253 Japanese subjects (134 diabetic patients and 119 healthy volunteers). Identified novel variations were as follows: -2772G>A, 2767_-2760delGGTGAACA, -2720T>C, -2547delG, -2545G>T, -2545_-2544 delGC, and -2040C>T in the enhancer region; -778C>T, -777G>A, -529G>C, -189C>A, and -185A>G in the promoter region; 151A>G (S51G), 481G>C (A161P), 986G>A (R329H), 1078G>A (D360N), and 1119C>T (D373D) in the exons, and IVS1+128T>A, IVS3+163G>A, IVS4+271A>G, IVS5-49A>G, IVS6-210C>T, IVS6-196T>A, IVS6-32T>A, IVS7+84G>A, IVS7-174C>T, and IVS8+64C>T in the introns. Since we found no significant differences in the variation frequencies between healthy volunteers and diabetic patients, the data for all subjects were treated as one group in further analysis. The allele frequencies were 0.265 for IVS6-196T>A, 0.045 for -2772G>A and -2720T>C, 0.024 for -2040C>T, 0.014 for IVS7-174C>T, 0.010 for -529G>C, 0.006 for IVS1+128T>A and 481G>C (A161P), 0.004 for -2767_-2760delGGTGAACA and IVS6-210C>T, and 0.002 for the other 17 variations. In addition, the two known nonsynonymous single nucleotide polymorphisms, 681G>A (splicing defect, (*)2 allele) and 636G>A (W212X; (*)3 allele) were detected at 0.267 and 0.128 frequencies, respectively. No variation was detected in the known binding sites for constitutive androstane receptor and glucocorticoid receptor. Linkage disequilibrium analysis showed several close linkages of variations throughout the gene. By using the variations, thirty-one haplotypes of CYP2C19 and their frequencies were estimated. Our results would provide fundamental and useful information for genotyping CYP2C19 in the Japanese and probably other Asian populations.