rs11203203 is associated with type 1 diabetes risk in population pre-screened for high-risk HLA-DR,DQ genotypes.

OBJECTIVE: To evaluate UBASH3A (rs11203203) as a predictor of persistent islet autoimmunity (IA) and type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: The Diabetes Autoimmunity Study in the Young (DAISY) followed prospectively for development of persistent IA (autoantibodies to insulin, GAD65, IA-2, or ZnT8 on at least two consecutive exams) and diabetes 1715 non-Hispanic white children at increased genetic risk for T1D. The DAISY participants were genotyped for rs11202203 (UBASH3A). RESULTS: UBASH3A allele A was associated with development of IA [hazard ratio (HR) = 1.46, 95%CI = 1.11-1.91, p = 0.007] and diabetes (HR = 1.84, 95%CI = 1.28-2.64, p = 0.001), controlling for presence of HLA-DR3/4,DQB1*0302 and having a first-degree relative (FDR) with T1D. The UBASH3A AA genotype conferred higher risk of persistent IA (12.7%) and diabetes (6.1%) by age 10 than for AG (7.7 and 3.1%, respectively) or GG (5.3 and 2.0%) genotype (p = 0.009 for IA, p = 0.0004 for diabetes). Among children with no family history of T1D, but HLA-DR3/4,DQB1*0302 and UBASH3A AA genotype, 35.9% developed IA and 50.6% developed diabetes by age 15. CONCLUSIONS: UBASH3A appears to be an independent predictor of IA and T1D in children, including those free of family history of T1D but carrying the HLA-DR3/4,DQB1*0302 genotype. If confirmed, UBASH3A may prove useful in T1D risk prediction and pre-screening of the general population children for clinical trials.

Secondary attack rate of type 1 diabetes in Colorado families.

OBJECTIVE: Families of children diagnosed with type 1 diabetes require counseling concerning type 1 diabetes risk in nondiabetic siblings and parents. No U.S. population-specific life-table risk estimates are currently available for parents, and those for siblings (2-6% by age 20 years) are based on family studies completed before 1987. RESEARCH DESIGN AND METHODS: We analyzed family histories of 1,586 patients in Colorado with type 1 diabetes (83% non-Hispanic white, 10% Hispanic, and 7% other) diagnosed before 16 years of age and interviewed during 1999-2002. Families of probands with type 2, undetermined, or secondary diabetes (n = 53) or those with incomplete data (n = 137) were excluded. The median age at onset of the proband was 7.1 years and the median diabetes duration 3.5 years. Cumulative risk estimates were calculated using survival analysis for 2,081 full siblings and 3,016 biological parents. RESULTS: In siblings, the overall risk of type 1 diabetes by age 20 years was 4.4%, but it was significantly (P < 0.0001) higher in siblings of probands diagnosed under age 7 years than in those diagnosed later. In parents, the overall risk by age 40 years was 2.6% and higher in fathers (3.6%) than in mothers (1.7%) of probands (P < 0.001). Similar to siblings, the risk was also higher (P = 0.006) in parents of probands diagnosed <7 years of age than in those diagnosed later. CONCLUSIONS: Current risks of type 1 diabetes in Colorado siblings and parents of type 1 diabetic probands are higher than in the 1982 Pittsburgh study but similar to contemporary European rates. Recurrence risk of type 1 diabetes is significantly higher in first-degree relatives of probands diagnosed at a young age.

Prediction of autoantibody positivity and progression to type 1 diabetes: Diabetes Autoimmunity Study in the Young (DAISY).

Diabetes Autoimmunity Study in the Young (DAISY) has followed 1972 children for islet autoimmunity and diabetes: 837 first-degree relatives of persons with type 1 diabetes and 1135 general population newborns identified through human leukocyte antigen (HLA) screening. During follow-up of 4.06 yr (range, 0.17-9 yr), serial determination of autoantibodies to glutamic acid decarboxylase, protein tyrosine phosphatase IA2, and insulin has generated approximately 20,000 results. Among 162 children with at least one positive autoantibody, in 31% the test was false positive (autoantibodies were negative twice on blinded duplicate aliquots), in 31% it was transiently positive (confirmed on blinded duplicate aliquots but negative on follow-up), and in 36% it was persistently positive. Using proportional hazards modeling, the HLA-DR3/4 DQ8 genotype, another positive autoantibody at the first positive visit, and level of autoantibody were predictive of persistent positivity. Only HLA-DR3/4 DQ8 genotype was predictive of progression to diabetes in proportional hazards modeling. This prospective study reveals that cross-sectional determination of islet autoantibodies in a population with relatively low previous probability of autoimmunity identifies as "positive" a large number of individuals who are either false or transiently positive. Predictive value of autoantibodies increases with blinded duplicate and independent sample retesting and incorporation of the level of autoantibody in the predictive algorithm.

Extrapancreatic autoantibody profiles in type I diabetes.

Type I diabetes (T1D) is an autoimmune disease characterized by destruction of insulin-producing ß-cells in the pancreas. Although several islet cell autoantigens are known, the breadth and spectrum of autoantibody targets has not been fully explored. Here the luciferase immunoprecipitation systems (LIPS) antibody profiling technology was used to study islet and other organ-specific autoantibody responses in parallel. Examination of an initial cohort of 93 controls and 50 T1D subjects revealed that 16% of the diabetic subjects showed anti-gastric ATPase autoantibodies which did not correlate with autoantibodies against GAD65, IA2, or IA2-ß. A more detailed study of a second cohort with 18 potential autoantibody targets revealed marked heterogeneity in autoantibody responses against islet cell autoantigens including two polymorphic variants of ZnT8. A subset of T1D subjects exhibited autoantibodies against several organ-specific targets including gastric ATPase (11%), thyroid peroxidase (14%), and anti-IgA autoantibodies against tissue transglutaminase (12%). Although a few T1D subjects showed autoantibodies against a lung-associated protein KCNRG (6%) and S100-ß (8%), no statistically significant autoantibodies were detected against several cytokines. Analysis of the overall autoantibody profiles using a heatmap revealed two major subgroups of approximately similar numbers, consisting of T1D subjects with and without organ-specific autoantibodies. Within the organ-specific subgroup, there was minimal overlap among anti-gastric ATPase, anti-thyroid peroxidase, and anti-transglutaminase seropositivity, and these autoantibodies did not correlate with islet cell autoantibodies. Examination of a third cohort, comprising prospectively collected longitudinal samples from high-risk individuals, revealed that anti-gastric ATPase autoantibodies were present in several individuals prior to detection of islet autoantibodies and before clinical onset of T1D. Taken together, these results suggest that autoantibody portraits derived from islet and organ-specific targets will likely be useful for enhancing the clinical management of T1D.

Age of islet autoantibody appearance and mean levels of insulin, but not GAD or IA-2 autoantibodies, predict age of diagnosis of type 1 diabetes: diabetes autoimmunity study in the young.

OBJECTIVE: We evaluated predictors of progression to diabetes in children with high-risk HLA genotypes and persistent islet autoantibodies. RESEARCH DESIGN AND METHODS: The Diabetes Autoimmunity Study in the Young (DAISY) followed 2,542 children with autoantibodies measured to GAD, IA-2, and insulin. RESULTS: Persistent islet autoantibodies developed in 169 subjects, and 55 of those progressed to diabetes. Children expressing three autoantibodies showed a linear progression to diabetes with 74% cumulative incidence by the 10-year follow-up compared with 70% with two antibodies and 15% with one antibody (P < 0.0001). Both age of appearance of first autoantibody and insulin autoantibody (IAA) levels, but not GAD or IA-2 autoantibodies, were major determinants of the age of diabetes diagnosis (r = 0.79, P < 0.0001). CONCLUSIONS: In the DAISY cohort, 89% of children who progressed to diabetes expressed two or more autoantibodies. Age of diagnosis of diabetes is strongly correlated with age of appearance of first autoantibody and IAA levels.

Enterovirus infection and progression from islet autoimmunity to type 1 diabetes: the Diabetes and Autoimmunity Study in the Young (DAISY).

OBJECTIVE: To investigate whether enterovirus infections predict progression to type 1 diabetes in genetically predisposed children repeatedly positive for islet autoantibodies. RESEARCH DESIGN AND METHODS: Since 1993, the Diabetes and Autoimmunity Study in the Young (DAISY) has followed 2,365 genetically predisposed children for islet autoimmunity and type 1 diabetes. Venous blood and rectal swabs were collected every 3-6 months after seroconversion for islet autoantibodies (against GAD, insulin, or insulinoma-associated antigen-2 [IA-2]) until diagnosis of diabetes. Enteroviral RNA in serum or rectal swabs was detected using reverse transcriptase PCR with primers specific for the conserved 5' noncoding region, detecting essentially all enterovirus serotypes. RESULTS: Of 140 children who seroconverted to repeated positivity for islet autoantibodies at a median age of 4.0 years, 50 progressed to type 1 diabetes during a median follow-up of 4.2 years. The risk of progression to clinical type 1 diabetes in the sample interval following detection of enteroviral RNA in serum (three diabetes cases diagnosed among 17 intervals) was significantly increased compared with that in intervals following a negative serum enteroviral RNA test (33 cases diagnosed among 1,064 intervals; hazard ratio 7.02 [95% CI 1.95-25.3] after adjusting for number of autoantibodies). Results remained significant after adjustment for ZnT8-autoantibodies and after restriction to various subgroups. Enteroviral RNA in rectal swabs was not predictive of progression to type 1 diabetes. No evidence for viral persistence was found. CONCLUSIONS: This novel observation suggests that progression from islet autoimmunity to type 1 diabetes may increase after an enterovirus infection characterized by the presence of viral RNA in blood.

Do non-HLA genes influence development of persistent islet autoimmunity and type 1 diabetes in children with high-risk HLA-DR,DQ genotypes?

OBJECTIVE: Specific alleles of non-HLA genes INS, CTLA-4, and PTPN22 have been associated with type 1 diabetes. We examined whether some of these alleles influence development of islet autoimmunity or progression from persistent islet autoimmunity to type 1 diabetes in children with high-risk HLA-DR,DQ genotypes. RESEARCH DESIGN AND METHODS: Since 1993, the Diabetes Autoimmunity Study in the Young (DAISY) has followed 2,449 young children carrying HLA-DR,DQ genotypes associated with type 1 diabetes. Of those, 112 have developed islet autoimmunity (persistent autoantibodies to insulin, GAD65, and/or IA-2), and 47 of these have progressed to type 1 diabetes. The influence of polymorphisms of INS(-23Hph1), CTLA-4(T17A), and PTPN22(R620W) on development of persistent islet autoimmunity and progression to type 1 diabetes was evaluated by parametric models and by survival analyses. RESULTS: PTPN22(R620W) allele T was associated with development of persistent islet autoimmunity (hazard ratio 1.83 [95% CI 1.27-2.63]) controlling for ethnicity, presence of HLA-DR3/4,DQB1*0302, and having a first-degree relative with type 1 diabetes. Survival analyses showed a significantly (P = 0.002) higher risk of persistent islet autoimmunity by age 10 years for the TT genotype (27.3%) than for the CT or CC genotype (7.9 and 5.3%, respectively). Cumulative risk of persistent islet autoimmunity was slightly higher (P = 0.02) for the INS(-23Hph1) AA genotype (7.8%) than for the AT or TT genotype (4.2 and 6.4% risk by age 10 years, respectively). CONCLUSIONS: Whereas the HLA-DR3/4,DQB1*0302 genotype had a dramatic influence on both development of islet autoimmunity and progression to type 1 diabetes, the PTPN22(R620W) T allele significantly influences progression to persistent islet autoimmunity in the DAISY cohort.

HLA-DPB1*0402 protects against type 1A diabetes autoimmunity in the highest risk DR3-DQB1*0201/DR4-DQB1*0302 DAISY population.

OBJECTIVE: A major goal in genetic studies of type 1A diabetes is prediction of anti-islet autoimmunity and subsequent diabetes in the general population, as >85% of patients do not have a first-degree relative with type 1A diabetes. Given prior association studies, we hypothesized that the strongest candidates for enhancing diabetes risk among DR3-DQB1*0201/DR4-DQB1*0302 individuals would be alleles of DP and DRB1*04 subtypes and, in particular, the absence of reportedly protective alleles DPB1*0402 and/or DRB1*0403. RESEARCH DESIGN AND METHODS: We genotyped 457 DR3-DQB1*0201/DR4-DQB1*0302 Diabetes Autoimmunity Study of the Young (DAISY) children (358 general population and 99 siblings/offspring of type 1 diabetic patients) at the DPB1, DQB1, and DRB1 loci using linear arrays of immobilized sequence-specific oligonucleotides, with direct sequencing to differentiate DRB1*04 subtypes. RESULTS: By survival curve analysis of DAISY children, the risk of persistently expressing anti-islet autoantibodies is approximately 55% for relatives (children with a parent or sibling with type 1 diabetes) in the absence of these two protective alleles vs. 0% (P = 0.02) with either protective allele, and the risk is 20 vs. 2% (P = 0.004) for general population children. Even when the population analyzed is limited to DR3-DQB1*0201/DR4-DQB1*0302 children with DRB1*0401 (the most common DRB1*04 subtype), DPB1*0402 influences development of anti-islet autoantibodies. CONCLUSIONS: The ability to identify a major group of general population newborns with a 20% risk of anti-islet autoimmunity should enhance both studies of the environmental determinants of type 1A diabetes and the design of trials for the primary prevention of anti-islet autoimmunity.

Association of the PTPN22/LYP gene with type 1 diabetes.

OBJECTIVES: The goal of this study was to verify the association between type 1 diabetes (T1D) and the protein tyrosine phosphatase, non-receptor type 22 (PTPN22) gene in non-Hispanic whites (NHWs) and Hispanics from Colorado. SUBJECTS AND METHODS: The C1858T single-nucleotide polymorphism within the PTPN22 gene was genotyped in 753 patients with T1D ascertained from the diabetes clinic at the Barbara Davis Center in Denver and 662 control population. RESULTS: Both the PTPN22 CT genotype [odds ratio (OR) = 1.96; p < 0.0001] and TT genotype (OR = 4.41; p = 0.02) were significantly associated with T1D in the NHW population. While the association was stronger in subjects with non-HLA-DR3/4 genotypes than in those with the HLA-DR3/4 genotype, regression analyses did not reveal significant interaction between PTPN22 genotypes and HLA-DR3/4. The strength of the association was similar in males and females, patients diagnosed before and after age 10 yr, and in Hispanics and NHWs. CONCLUSION: In this study, we confirm that PTPN22 is associated with T1D in the Colorado population.

Extreme genetic risk for type 1A diabetes.

Type 1A diabetes (T1D) is an autoimmune disorder the risk of which is increased by specific HLA DR/DQ alleles [e.g., DRB1*03-DQB1*0201 (DR3) or DRB1*04-DQB1*0302 (DR4)]. The genotype associated with the highest risk for T1D is the DR3/4-DQ8 (DQ8 is DQA1*0301, DQB1*0302) heterozygous genotype. We determined HLA-DR and -DQ genotypes at birth and analyzed DR3/4-DQ8 siblings of patients with T1D for identical-by-descent HLA haplotype sharing (the number of haplotypes inherited in common between siblings). The children were clinically followed with prospective measurement of anti-islet autoimmunity and for progression to T1D. Risk for islet autoimmunity dramatically increased in DR3/4-DQ8 siblings who shared both HLA haplotypes with their diabetic proband sibling (63% by age 7, and 85% by age 15) compared with siblings who did not share both HLA haplotypes with their diabetic proband sibling (20% by age 15, P < 0.01). 55% sharing both HLA haplotypes developed diabetes by age 12 versus 5% sharing zero or one haplotype (P = 0.03). Despite sharing both HLA haplotypes with their proband, siblings without the HLA DR3/4-DQ8 genotype had only a 25% risk for T1D by age 12. The risk for T1D in the DR3/4-DQ8 siblings sharing both HLA haplotypes with their proband is remarkable for a complex genetic disorder and provides evidence that T1D is inherited with HLA-DR/DQ alleles and additional MHC-linked genes both determining major risk. A subset of siblings at extremely high risk for T1D can now be identified at birth for trials to prevent islet autoimmunity.

Clinical features of children with screening-identified evidence of celiac disease.

OBJECTIVE: At-risk groups commonly undergo screening for autoantibodies associated with celiac disease (CD). However, the clinical significance of a positive test remains uncertain. The objective of this study was to evaluate growth and clinical features of children who test positive for an autoantibody associated with CD. METHODS: A case-control study of Denver area healthy infants and young children with and without CD autoantibodies was conducted. A cohort of HLA-characterized children were followed prospectively since birth for the development of immunoglobulin A antitissue transglutaminase autoantibodies (TG). Clinical evaluation, questionnaire, blood draw, and small bowel biopsy were performed. Growth and nutrition and frequency of positive responses were measured. RESULTS: Compared with 100 age- and gender-matched TG-negative controls, 18 TG-positive children, 5.5 +/- 0.5 years of age, had a greater number of symptoms and lower z scores for weight-for-height and for body mass index. Responses that were independently associated with TG-positive status were irritability/lethargy, abdominal distention/gas, and difficulty with weight gain. CONCLUSIONS: Screening-identified TG-positive children demonstrate mild alterations in growth and nutrition and report more symptoms than control subjects. Additional study is needed on the benefit and risk of identifying CD in at-risk groups.

A prospective study of the incidence of childhood celiac disease.

OBJECTIVES: To estimate the frequency of celiac disease (CD) in children in the general population of Denver, Colorado. STUDY DESIGN: From 22,346 newborns characterized as expressing 0, 1, or 2 HLA-DR3(DQB1*0201) alleles, 987 were selected for a prospective stratified cohort study. Participants were followed for as long as 7 years with serial testing for serum IgA anti-transglutaminase antibodies and for evidence of CD (intestinal mucosal changes or persistent seropositivity). RESULTS: Of 40 children with at least one positive serologic test, 19 had evidence of CD (10 by biopsy, 9 by persistent seropositivity). Those expressing 0, 1, or 2 HLA-DR3 alleles had, respectively, 0.3% (95% CI, 0.0-2.7), 3.4% (3.0-11.7), and 3.2% (1.0-11.0) risk for evidence of CD by age 5 years. The adjusted risk estimate for evidence of CD by age 5 years for the Denver general population was 0.9% (0.4-2.0), or 1 in 104 (1:49-221). After adjusting for number of HLA-DR3 alleles expressed, risk was higher in females: RR=3.34 (1.00-10.9, P=.048). Evidence of CD was not observed before age 2.6 years. CONCLUSIONS: Celiac disease may affect 0.9% of Denver children by 5 years of age. Children positive for the HLA-DR3 allele and females appear to be at increased risk.