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Clinical Research: Twin Family Study of Islet Cell Autoimmunity

Clinical Research: The Barbara Davis Center Twin Family Study of Islet Cell Autoimmunity follows identical and fraternal twins (and triplets) if one twin has been diagnosed with Type 1 diabetes.

Who is eligible?

  1. Twins who are affected with type 1 diabetes and their unaffected co-twins, non-twin siblings, and parents. Type 1 diabetes in the affected twin is defined as onset < age 40 and the use of daily insulin therapy within one year of diagnosis.
  2. Twins diagnosed ≥ age 40 may be eligible if documented by the presence of islet cell autoantibodies.
  3. The unaffected twin may be any age if his twin with diabetes falls into 1 of the 2 above categories.
  4. Twins who are concordant for type 1 diabetes may be included in the study if one twin was tested for autoantibodies prior to the development of diabetes, as may be the case for subjects in DPT-1 or TrialNet. 

How are family members screened and for what?
Blood tests using DNA and serum samples are analyzed for all family members (1) to measure diabetes-related autoantibodies (which may appear years before diabetes develops), including islet cell, celiac, and adrenal autoantibodies and (2) to characterize gene variants associated with increased and decreased risk for diabetes, including immune systems genes such as HLA-DRB1, HLA-DQA1and HLA-DQB1 as well as theINS, CTLA4, PTPN22, and VDR genes.. There is no cost for these tests.

What happens if I do have autoantibodies?
Additional tests will be offered to confirm islet cell autoantibody positivity and to estimate your chances of developing type 1 diabetes. Any family member positive for celiac or adrenal autoantibodies will be referred to the appropriate health care provider. All research volunteers will be closely monitored for early detection of type 1 diabetes. Unaffected twins and siblings will be followed every 1-2 years for islet cell antibodies. Results from TrialNet will be used for antibody testing for those members who are also enrolled in TrialNet.

Why should I participate?
Twins are very rare and cases in which one or both twins have type 1 diabetes are even rarer. Studies of twins and their families are especially helpful for finding the genes and environmental triggers that cause type 1 diabetes. Our research team has already learned a great deal by studying affected and unaffected co-twins of patients with type 1 diabetes. Our current results indicate that genes play a very important role in different stages in the development of type 1 diabetes and in other autoimmune diseases that often occur together with type 1 diabetes. We also believe genes determine many other aspects of diabetes, including how an individual will respond to preventive agents or treatment aimed at preserving insulin-producing cells. Because markers for the development of diabetes occur prior to the diagnosis of diabetes, we look at the potential development of diabetes over time and how differences in genes and environmental exposures promote or inhibit the development of diabetes. We will keep you informed of the results of ongoing research studies and of any new research studies. If you agree to participate in the registry, you may withdraw at any time.

Who should I call with questions or to schedule an appointment?
Alexandra Fouts: 1.303.724.6774 or

Principal Investigators: Andrea Steck, MD