Type 1 Diabetes Genetics Consortium (T1DGC)

General Description

The Type 1 Diabetes Genetics Consortium (T1DGC) was an international, multicenter program organized to promote research to identify genes and alleles that determine an individual's risk for type 1 diabetes. The program had two primary goals: (1) to identify genomic regions and candidate genes whose variants modify an individual’s risk of type 1 diabetes and help explain the clustering of the disease in families and (2) to make research data available to and establish resources that can be used by the research community. The T1DGC assembled a resource of affected sib-pair families, parent-child trios, and case-control collections with banks of DNA, serum, plasma, and EBV-transformed cell lines. In addition to T1DGC-recruited ASP families, the T1DGC recruited trio families from ethnic groups with lower prevalence of type 1 diabetes. The T1DGC also welcomed the inclusion of earlier ascertained case-control collections (from the UK, Denmark, etc.). Research with T1DGC data has included genome-wide linkage scans, evaluation of the human major histocompatibility complexes, examination of published candidate genes for type 1 diabetes, and examination of autoimmune disease genes and those affecting β-cell function in type 2 diabetes.

In 2007, the T1DGC incorporated over 7,000 cases from the UK (the JDRF/WT case series, aka GRID). GRID samples are available here, and data from dbGaP, the European Genome-phenome Archive (EGA) and data and documentation at the JDRF/WT DIL.

Objectives

Goals of the T1DGC include identifying genomic regions and candidate genes whose variants modify an individual’s risk of type 1 diabetes and help explain the clustering of the disease in families, making research data available to the research community, and establishing resources that can be used by the research community.

Outcome Measure

Outcome measures included the establishment of resources for research into the genetic origins of type 1 diabetes and identification of genomic regions and genes whose variants contribute to an individual’s risk of type 1 diabetes.

Criteria

The desired ASP family structure was two affected siblings, both biological parents, and up to two unaffected siblings. The minimum family structure was two affected siblings. Eligibility criteria include the following:

1. Siblings with diagnosis of type 1 diabetes;
2. Diagnosis before 35 years of age;
3. Use of insulin within 6 months of diagnosis;
4. Continuous use of insulin (without stopping for 6 months or more); and
5. Informed consent for blood collection, genetic analysis, and exam (i.e., family history, other autoimmune diseases).

In addition, trio families were collected in selected populations with a low prevalence of the disease throughout the Asia-Pacific, European and North American Networks. The required family structure was an affected child and both biological parents. Eligibility criteria are the same as listed above.
Cases and controls were collected throughout the Asia-Pacific, European and North American Networks in selected low-prevalence populations. Eligibility criteria for cases are the same as above.

Outcome

The T1DGC has assembled renewable genetic materials for use in family based linkage and association studies and made research data available to the research community. Phenotype and genotype data from study participants has been used in research studies concerning the genetic origins of T1D risk in families and the general population.