广西地区壮族Graves病与CTLA4基因多态性相关性研究

目的分析CTLA4基因微卫星多态性与广西地区壮族Graves病（Graves’disease，GD）相关性。方法提取48例广西地区壮族GD患者和44名正常对照组的外周血白细胞基因组DNA，应用聚合酶链反应检测CTLA4第4外显子的3’非翻译区包含（AT）n[CTLA4（AT）n]重复序列的特异性等位基因。结果广西地区壮族人CTLA4微卫星多态性检出19种等位基因。壮族GD组106bp等位基因频率与正常对照组比较显著增高，差异有统计学意义（P〈0．05）。结论广西壮族GD患者与CTLA4基因多态性明显相关,CTA4（AT）n 106bp可能是广西壮族GD的易感等位基因。     

特发性扩张型心肌病CTLA-4基因3''非翻译区(AT)n微卫星多态性研究

目的 特发性扩张型心肌病（idiopathic dilated cardiomyopathy，IDC）的发病机制与T细胞免疫应答密切相关。细胞毒性T淋巴细胞相关抗原-4（cytotoxic T lymphocyte antigen-4，CTLA-4）主要在已激活的T细胞上表达，通过与CIY28竞争结合B7，抑制T细胞过度激活，维持免疫系统内环境稳定。CTLA-4基因3’非翻译区（AT）n微卫星多态性影响CTLA-4功能。本研究旨在探讨外周血单个核细胞（PBMC）CTLA-表达状况及3’非翻译区（AT）n微卫星基因多态性与IDC的相关性。方法分别用原位杂交、免疫组化、序列特异性引物PCR等方法检测38例无血缘关系的北方汉族IDC患者以及50例正常对照者的CTLA-4mRNA、蛋白质表达、CTLA-4基因外显子3’末端非翻译区（AT）n重复序列多态性，并对PCR扩增产物进行序列分析。结果IDC组与对照组相比，PBMC经金黄色葡萄球菌肠毒素B刺激后CTLA-4mRNA、蛋白质表达强度显著减弱，且无一定规律；3’末端非翻译区共发现18种CTLA-4等位基因，与对照组比较，106bp等位基因频率在IDC患者中显著增高[22．22％ vs 1％，P=0．0002．OR=23．56，95％可信区间（CI）：9．65～83．74]。结论IDC患者CTLA-4基因转录和表达缺陷，该缺陷与CTLA-4基因3’末端非翻译区（AT）n重复序列多态性存在关联。     

特发性扩张型心肌病CTLA-4基因3′非翻译区(AT)n微卫星多态性研究

目的特发性扩张型心肌病(idiopathic dilated cardiomyopathy,IDC)的发病机制与T细胞免疫应答密切相关。细胞毒性T淋巴细胞相关抗原24(cytotoxic Tlymphocyte antigen-4,CTLA-4)主要在已激活的T细胞上表达,通过与CD28竞争结合B7,抑制T细胞过度激活,维持免疫系统内环境稳定。CTLA-4基因3′非翻译区(AT)n微卫星多态性影响CTLA-4功能。本研究旨在探讨外周血单个核细胞(PBMC)CTLA-4表达状况及3′非翻译区(AT)n微卫星基因多态性与IDC的相关性。方法分别用原位杂交、免疫组化、序列特异性引物PCR等方法检测38例无血缘关系的北方汉族IDC患者以及50例正常对照者的CTLA-4 mRNA、蛋白质表达、CTLA24基因外显子3′末端非翻译区(AT)n重复序列多态性,并对PCR扩增产物进行序列分析。结果IDC组与对照组相比,PBMC经金黄色葡萄球菌肠毒素B刺激后CTLA-4 mRNA、蛋白质表达强度显著减弱,且无一定规律;3′末端非翻译区共发现18种CTLA24等位基因,与对照组比较,106bp等位基因频率在IDC患者中显著增高[22.22%vs1%,P=0.0002,OR=23.56,95%可信区间(CI):9.65～83.74]。结论IDC患者CTLA-4基因转录和表达缺陷,该缺陷与CTLA-4基因3′末端非翻译区(AT)n重复序列多态性存在关联。     

CTLA-4基因多态性调节溃疡性结肠炎患者CTLA-4 mRNA稳定性和蛋白水平

目的 研究细胞毒T淋巴细胞相关抗原4(cytotoxic T-lymphocyte associated antigen 4,CTLA-4)基因3'非转录区(AT)n重复序列多态性对溃疡性结肠炎(ulcerative colitis,UC)患者CTLA-4mRNA稳定性和基因表达的影响.方法 采用实时定量PCR方法检测膜型CTLA-4(full length CTLA-4,flCTLA-4)和可溶性CTLA-4(soluble CTLA-4,sCTLA-4)mRNA表达,半衰期法分析其mRNA稳定性.免疫组化检测flCTLA-4蛋白表达.酶联免疫吸附实验测定sCTLA-4蛋白水平.荧光PCR-毛细管电泳技术检测300例UC患者和700名健康对照者CTLA-4基因(AT)n重复序列多态性.结果 活动期UC患者肠黏膜sCTLA-4 mRNA的表达显著低于缓解期UC患者(P=0.004).在UC患者中,(AT)n重复序列长等位基因携带者表达低水平的flCTLA-4和sCTLA-4 mRNA以及sCTLA-4蛋白(均P＜0.01).携带长等位基因的UC患者CTLA-4 mRNA的稳定性明显降低.UC患者CTLA-4基因(AT)n重复序列长等位基因携带者(≥116 bp)频率显著高于正常对照组(P＜0.01),且与广泛型结肠炎相关(P=0.008).结论 UC患者CTLA-4基因(AT)n重复序列多态性与CTLA-4基因表达水平相关,携带(AT)n重复序列长等位基因的UC患者CTLA-4 mRNA及蛋白的表达降低,提示CTLA-4基因在UC遗传免疫发病机制中起重要作用.     

CTLA-4基因外显子4区AT重复序列多态性及碘摄入量与Graves病的相关性研究

目的 探讨细胞毒性T淋巴细胞相关抗原-4(cytotoxic T lymphocyte associated antigen-4,CTLA-4)基因第4外显子区AT重复序列多态性多态性[CTLA-4(AT)n]及碘摄入状况与粤西汉族人Graves病(Graves disease,GD)发病的相关性.方法 收取2006年...     

精神分裂症与六种候选功能基因的关联研究

目的：探讨多巴胺D2受体基因（dopamine D2 receptor,DRD2)、多巴胺D4受体基因（DRD4）、5－羟色胺2A受体基因（5－hydroxytryptamine 2A receptor,5-HT2A),5-羟色胺6受体基因（5－HT6)、儿茶酚胺氧位甲基转移酶基因（catechol-O-methyltransferase,COMT)和多巴胺转运体基因（dopamine transferase,DAT1)多态性与精神分裂症的关系。方法：应用基因扩增片段长度多态和基因扩增的限制性片段长度多态技术，对中国汉族人群中67例精神分裂症患者与上述6种候选功能和基因扩增的限制性片段长度多态技术，对中国汉族人群中67例精神分裂症患者与上述6种候选功能基因进行遗传关联分析。结果：（1）DRD2、5－HT2A、5－HT6和KCOMT的基因型和等位基因频率在患者组和对照组中差异无显著性（P＞0．05）。（2）DRD4基因中6次重复序列等位基因、DAT1基因中480bp等位基因和480／520基因型在两组中差异有显著性，Z分别为2．03、2．05和2．05；P均小于0．05。（3）经关联分析后，仅DAT1基因的480bp等位基因的比值比为0．441，95％可信区间为0．202－0．963，并有显著性意义（Z＝2．05，P＜0．05），而DAT1的480／520基因型和DRD4和6次重复序列等位基因的比值比分别为0．128和0．123，但Z均小于1．96，无显著性意义（P＞0．05）。因此，6个功能基因中仅DAT1的480bp等位基因与精神分裂症呈负关联。结论：中国汉族人群中DAT1基因的480bp等位基因与精神分裂症间存在负关联，支持精神分裂症的多巴胺假说。     

B7-H4基因多态性与乳腺浸润性导管癌预后的相关性研究

目的探讨B7-H4基因rs10754339、rs10801935和rs3738414等单核苷酸多态性（SNP）位点多态性与黑龙江省妇女乳腺浸润性导管癌预后的相关性。方法取280例乳腺浸润性导管癌患者的外周血提取基因组DNA,利用聚合酶链式反应限制性片段长度多态性（PCR．RFLP）技术进行B7．H4单核苷酸多态性检测,引用统计学软件分析基因多态性与患者临床指标（包括肿瘤大小,淋巴结转移,以及雌激素受体、孕激素受体和P53基因的表达）间的关系（卡方检验计算P值）,进而确定该基因与黑龙江省汉族妇女乳腺癌预后的相关性。结果B7-H4基因的rs10754339中,AA和AG基因型发生频率在雌激素受体表达阳性和阴性患者中有统计学差异（Х^2=4．06,P〈0．05;Х^2=3．97,P〈0．05）,AA基因型和G等位基因发生频率在孕激素受体表达阳性和阴性患者中有显著差异（Х^2=4．74,P〈0．05;Х^2=5．30,P〈0．05）。rs10801935中,AA基因型和C等位基因发生频率在孕激素受体表达阳性和阴性患者中有显著差异（Х^2=5．36,P〈0．05;Х^2=5．90,P〈0．05）,而AC基因型发生频率在P53基因表达阳性和阴性患者中有显著差异（Х^2=5．82,P〈0．05）。结论B7-H4基因多态性与乳腺浸润性导管癌患者雌激素受体,孕激素受体及P53基因的表达有关联,与乳腺癌患者的预后有一定相关性。     

中国山东沿海地区汉族男性人群白介素-23受体基因多态性与痛风的易感性研究

目的探讨中国山东省沿海地区汉族男性群体的白细胞介素23受体（IL-23R）基因rs7517847位点G／T的多态性是否与痛风的易感性有关。方法选取202例痛风患者和346例健康对照者,检测中国汉族男性群体的IL-23受体内含子区rs7517847位点基因多态性分布,数据经,检验得出其与痛风发病的遗传易感性的关系。结果经,检验,痛风组和对照组中IL-23R基因rs7517847位点GG,GT和1Tr基因型频率（10．4％,49．5％,40．1％;16．2％,49．7％,34．1％;X^2=4．305,P〉0．05）与等位基因频率G和T（35．1％,41％;64．9％,59％;X^2=3．727,P〉0．05）均无统计学意义。IL-23R基因rs7517847位点G／T基因多态性与痛风病的危险因素无显著性关联。结论尚不能认为中国沿海地区汉族男性人群中IL-23R内含子区rs7517847位点基因多态性与痛风有关联性。     

血管内皮生长因子基因多态性与克罗恩病的相关性CSCD

目的探讨血管内皮生长因子（vascular endothelial growth factor,VEGF）基因多态性与克罗恩病（Crohn’S disease,CD）易感性的关系。方法收集275例CD患者和495名性别、年龄相匹配的健康对照者,采用SNaPshot技术检测VEGF基因rs699947和rs3025039位点的等位基因和基因型频率。结果CD组与对照组之间整体比较,VEGF基因rs699947和rs3025039位点的变异等位基因和基因型频率差异无统计学意义（P均〉o．05）。分层分析发现,结肠型CD患者中rs699947的变异等位基因（A）和基因型（CA＋AA）频率显著高于对照组（P=0．006,95％CI：1．143～2．234;P=0．005,95％CI：1．203～2．900）。与对照组相比,回肠受累（回肠末段型＋回结肠型）的CD患者中,rs699947的变异等位基因（A）和基因型（CA4-AA）频率偏低（P=0．033,95％CI：0．524～0．974;P=0．043,95％CI：0．481～0．989）。此外,非狭窄非穿透型CD患者中rs3025039纯合子变异基因型（TT）频率低于对照组（0．62％vs．4．85％,P=0．036,95％CI：0．016～O．870）。结论VEGF基因rs699947位点基因变异可能增加结肠型CD的发病风险,但在回肠受累的CD患者中可能发挥保护作用。VEGF基因rs3025039位点的纯合子变异基因型（TT）携带者中非狭窄非穿透型CD的发病风险可能降低。     

Association of CTLA-4 variants with susceptibility to inflammatory bowel disease: A meta-analysis

Objective

The aim of this study was to determine whether CTLA-4 gene variants were associated with susceptibility to inflammatory bowel disease (IBD).

Methods

Meta-analysis was conducted on the association between CTLA-4 variants and IBD using: (1) allelic contrast, (2) the recessive model, and (3) the dominant model.

Results

A total of 9 relevant studies including 1739 Crohn’s disease (CD) cases, 10 relevant studies containing 1017 ulcerative colitis (UC) cases and 2685 healthy controls were involved in this meta-analysis. Overall, CTLA-4+49A/G, −318C/T and CT60 variants were not associated with IBD susceptibility in all genetic models (P > 0.05). Stratification by ethnicity indicated a significant association between the CTLA-4+49A/G variant and CD in Caucasian group (GG vs. GA + AA: OR = 0.723, 95% CI = 0.564–0.926, P = 0.010). In Asian group, meta-analysis showed a significant association between the CTLA-4 CT60 variant and UC (AA vs. AG + GG: OR = 0.375, 95% CI = 0.163–0.861, P = 0.021).

Conclusions

Based on the published literature, this meta-analysis suggests that the CTLA-4+49A/G variant may be related to CD susceptibility in Caucasians, and the CTLA-4 CT60 variant may be associated with UC susceptibility in Asians.     

CTLA-4 polymorphisms and susceptibility to inflammatory bowel disease: A meta-analysis

Objective

The aim of this study was to explore whether the cytotoxic T lymphocyte associated antigen-4 (CTLA-4) polymorphisms are associated with susceptibility to ulcerative colitis (UC) and Crohn’s disease (CD).

Methods

The authors conducted a meta-analysis on associations between CTLA-4 +49 A/G, −318 C/T, CT60 A/G polymorphisms, and (AT)n repeat in the 3′ untranslated region (UTR) and UC and CD susceptibility.

Results

A total of 15 comparison studies were considered in our meta-analysis. Meta-analysis revealed no association between UC and the CTLA-4 +49 G and CTLA-4 −318 T alleles in all subjects (OR = 0.982, 95% CI = 0.851–1.1339, p = 0.804; OR = 0.500, 95% CI = 0.223–1.124, p = 0.094). No association was found between UC and the CTLA-4 CT60 A/G polymorphism in Europeans. However, a significant association was observed between the longer allele (?118 bp) of the (AT)n and UC in Asian population (OR = 6.073, 95% CI = 4.246–8.684, p = 1.0 × 10⁻⁹). Meta-analysis of the CTLA-4 +49 A/G, −318 C/T, CT60 A/G polymorphisms showed no association with CD.

Conclusions

This meta-analysis demonstrates that the CTLA-4 (AT)n repeat in 3′ UTR may be associated with susceptibility to UC in Asians, while no association was found between the CTLA-4 +49 A/G, −318 C/T, and CD60 A/G polymorphism and susceptibility to UC and CD.     

The length of the CTLA-4 microsatellite (AT)N-repeat affects the risk for type 1 diabetes. Diabetes Incidence in Sweden Study Group

CTLA-4 is important to down-regulating T cell responses and has been implicated in type 1 (insulin dependent) diabetes mellitus in both linkage and association studies. The aim of our study was to relate the polymorphic (AT)n microsatellite in the 3' untranslated sequence of the CTLA-4 gene to diabetes risk. We studied 616 consecutively diagnosed 0-34 year-old Swedish patients and 502 matched controls by PCR-based genotyping fo determine the length of the 3'-end (AT)n repeat region of the CTLA-4 gene and categorizing alleles as predominantly monomorphic short (S) or highly polymorphic (in length) long (L) alleles. The odds of type 1 diabetes of subjects with the L/L genotype was estimated to be 1.84 times that of subjects with the S/S genotype (95% CI 1.44-2.73, p=0.002). Further analysis of the long alleles, partitioned into intermediate (I) length and very long (VL) alleles, suggested that L alleles act recessively in conferring diabetes risk (p=0.0009). This study suggests that the 3'-end (AT)n repeat region of the CTLA-4 gene represents a recessive risk factor for type 1 diabetes.     

Polymorphisms in CTLA-4 predict de novo donor specific antibody formation after kidney transplantation

The post-transplant development of donor-specific antibodies (DSAs) initiates the antibody-mediated rejection, which is associated with an increased rate of graft loss. Therefore, risk prediction of de novo DSA (dnDSA) is important for understanding long-term prognostic implications for kidney transplantation outcomes. Cytotoxic T lymphocyte antigen-4 (CTLA-4), a cell surface molecule, suppresses T cell responses. Single-nucleotide polymorphisms (SNPs) in CTLA-4 are known to be associated with acute rejection; however, their association with dnDSA formation is not established. In the present study, we investigated the impact of CTLA-4 SNPs on dnDSA formation after kidney transplantation (KT) by analyzing three CTLA-4 SNPs (rs231775, rs3087243, and rs5742909) in 88 recipients. Patients with the GG genotype of CTLA-4 SNPs rs231775 and rs3087243 had higher rates of dnDSA formation than patients with the AA genotype or heterozygous genotypes. In conclusion, our findings indicate that CTLA-4 SNPs are predisposing factors for dnDSA formation after KT.     

CTLA-4, CD28, and ICOS gene polymorphism associations with non-small-cell lung cancer

Polymorphisms in genes encoding CD28, ICOS, and CTLA-4 were demonstrated to be associated with susceptibility to malignancies. To the best of our knowledge, no study on this association has been performed in a Caucasian population for non-small-cell lung cancer (NSCLC). In the present work, we investigated the polymorphisms CTLA-4c.49A>G (rs231775), CTLA-4g.319C>T (rs5742909), CTLA-4g.*642AT(8_33), CTLA-4g.*6230G>A (CT60) (rs3087243), CTLA-4g.*10223G>T (Jo31) (rs11571302), CD28c.17+3T>C (rs3116496), and ICOSc.1554+4GT(8_15) in 208 NSCLC patients and 326 controls. The distributions of the allele and genotype were similar in both groups for CTLA-4, CD28, and ICOS gene polymorphisms. However, we noted a tendency toward overrepresentation of individuals possessing the CTLA-4c.49A>G[A] allele in NSCLC patients compared with controls (0.84 vs 0.79, p = 0.09). The association became significant compared with controls in women for the CTLA-4c.49A>G[A] allele and CTLA-4c.49A>G[AA] genotype (0.67 vs 0.54, p = 0.01, and 0.47 vs 0.30, p = 0.02; respectively). Moreover, the constellation of alleles CTLA-4c.49A>G[A]/CT60[G]/CD28c.17+3T>C[T]/ICOSc.1554+4GT(8_15)[>10] increased the risk of NSCLC about 2-fold (p = 0.002). The same constellation of alleles combined with smoking, CTLA-4g.319C>T[T], and ICOSc.1554+4GT(8_15)[>10] was associated with a decreased overall survival rate. In conclusion, the constellation of specific alleles in CTLA-4, CD28, and ICOS genes contributes to the susceptibility and clinical course of NSCLC.     

Polymorphisms in the CTLA-4 Gene and Rheumatoid Arthritis Susceptibility: A Meta-analysis

Introduction

The +49A/G polymorphism and CT60 polymorphism in the CTLA-4 gene have been extensively examined for the association with rheumatoid arthritis (RA); however, results of different studies have been inconclusive. The aim of this study is to comprehensively evaluate the genetic risks of +49A/G and CT60 polymorphisms in the CTLA-4 gene for RA.

Methods

A meta-analysis was carried out to analyze the association of +49A/G and CT60 polymorphisms with RA risk.

Results

A total of 30 case?Ccontrol studies in 20 articles were included in this meta-analysis. The results indicated that the variant G allele carriers (GG + GA) of +49A/G polymorphism had an 18% increased risk of RA when compared with the homozygote AA (odds ratio (OR)?=?1.18, 95% confidence interval (CI): 1.04?C1.34 for GG + AG vs. AA). In addition, the variant CT60 A allele carriers of CT60 polymorphism had a 14% decreased risk of RA when compared with the homozygote GG (OR?=?0.86, 95%CI?=?0.78?C0.95 for AA + AG vs. GG). In the subgroup analysis by ethnicity, significant elevated RA risks were associated with +49G allele carriers in Asians, but not in Europeans. However, for CT60 polymorphism, significant decreased RA risks were associated with CT60 A allele carriers in Europeans, but not in Asians.

Conclusions

This meta-analysis suggested that the +49A/G and CT60 polymorphisms in the CTLA-4 gene may be risk factors for RA.     

CTLA-4 Gene Polymorphisms in Tunisian Patients with Graves' Disease

Graves' disease (GD) is an organ-specific autoimmune disorder of multifactorial etiology with a polygenic mode of inheritance. A recent report has demonstrated that there is a linkage and an association between the genetic markers of the CTLA-4 gene on chromosome 2q33 and GD. In order to confirm this association in a Tunisian population, three polymorphisms of the CTLA-4 gene were analyzed: the first is at the -318 position from the ATG start codon consisting of a C/T change; the second is in position 49 of exon 1, which lies in the A/G transition; and the third is in the 3' untranslated region with variant lengths of the dinucleotide (AT)n repeat. The genomic DNA from 144 patients with GD and 205 healthy individuals was genotyped after specific polymerase chain reaction amplification. Comparative analysis using a chi(2) test showed a weak yet significant difference in allele frequencies of the A/G dimorphic marker between patients and controls (P < 0.05), and a significant increase of A/A homozygous individuals among patients (21.53 vs 12.7%, P = 0.02, odds ratio (OR) = 1.89) was found. Analyses of CTLA-4 A/G polymorphism with respect to sex showed a significant difference in A/A genotypes between female patients and controls (OR = 2.14; 95%, 1.13 < OR < 4.04, P < 0.05). The distribution of CTLA-4 (AT)n allele frequencies differed between patients and controls (chi(2) = 38.18, 20 degrees of freedom, P = 0.0084) and the highest OR was found with the CTLA-4 (AT)-224-bp allele (OR = 6.43, 1.7 < OR < 28.64; P = 0.001). In conclusion, these results show that the CTLA-4 gene, or one closely associated with it, confers susceptibility to GD in a Tunisian population.     

Meta-Analysis: The Relationship Between CTLA-4 +49 A/G Polymorphism and Primary Biliary Cirrhosis and Type I Autoimmune Hepatitis

Objectives: CTLA-4 exon-1 +49A?>?G (rs231775) polymorphism has been reported to influence the risk for primary biliary cirrhosis (PBC) as well as type I autoimmune hepatitis (AIH-1) in many studies; however, the results still remain controversial and ambiguous. This study aimed to determine more precise estimations for the relationship between CTLA-4 +49 A?>?G polymorphism and the risk for PBC and AIH-1 by using a meta-analysis.

Design and Methods: PubMed, EMBASE and MEDLINE were searched. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association.

Results: Fifteen studies including 3661 patients with PBC and 4427 controls as well as seven studies including 1270 patients with AIH-1 and 1614 controls were identified. Our pooled analysis revealed that G allele of CTLA-4 gene +49A/G polymorphism may confer an increased risk of PBC in overall (p?=?0.001, OR?=?1.29; 95% CI?=?1.13–1.47) and Caucasians (p?=?0.001, OR?=?1.32; 95% CI?=?1.21–1.44). At genotypic level, the codominant, dominant and recessive models showed no significant association with PBC. With respect to AIH-1, the AG genotype demonstrated a trend for association with increased risk of AIH-1 (p?=?0.04, AG vs. AA, OR?=?1.20; 95% CI?=?1.01–1.43). However, the CTLA-4 alleles as well as genotypes in dominant and recessive models were not associated with a risk for AIH-1 in both Caucasians and Asians.

Conclusions: This meta-analysis concluded that the CTLA-4 G allele and the AG genotype were associated with an increased risk for PBC and AIH-1, respectively, suggesting the CTLA-4 +49 A/G polymorphism as a candidate of susceptibility locus to PBC and AIH-1.     

The Length of the CTLA-4 Microsatellite (AT)N-Repeat Affects the Risk for Type 1 Diabetes: For the Swedish Childhood Diabetes Study Group

CTLA-4 is important to down-regulating T cell responses and has been implicated in type 1 (insulin dependent) diabetes mellitus in both linkage and association studies. The aim of our study was to relate the polymorphic (AT)_n microsatellite in the 3′ untranslated sequence of the CTLA-4 gene to diabetes risk. We studied 616 consecutively diagnosed 0-34 year-old Swedish patients and 502 matched controls by PCR-based genotyping to determine the length of the 3′-end (AT)_n repeat region of the CTLA-4 gene and categorizing alleles as predominantly monomorphic short (S) or highly polymorphic (in length) long (L) alleles. The odds of type 1 diabetes of subjects with the L/L genotype was estimated to be 1.84 times that of subjects with the S/S genotype (95% CI 1.44-2.73, p=0.002). Further analysis of the long alleles, partitioned into intermediate (I) length and very long (VL) alleles, suggested that L alleles act recessively in conferring diabetes risk (p=0.0009). This study suggests that the 3′-end (AT)_n repeat region of the CTLA-4 gene represents a recessive risk factor for type 1 diabetes