Principal Investigator Dr. Robin Goland Purpose of Study To determine risk of development of type 1 diabetes in relatives of people with type 1 diabetes.  Subjects have a simple blood test to measure antibodies against islet cells.  About 96% of relatives of someone with type 1 diabetes will have no measurable antibodies and therefore a low risk of subsequent development of type 1 diabetes.  The 4% of relatives who test positive for islet antibodies will be eligible for confirmatory testing and for consideration of future trials aimed at preventing type 1 diabetes. Who is Eligible for the Study? Age:  Between 1 and 45 years old Type of Diabetes:  Type 1 diabetes Ideal Candidate:  Siblings, mothers, fathers, cousins of people with type 1 diabetes Exclusion criteria:  Subjects older than 45 Time Commitment:  Visit for blood test, about 15 minutes.  Subjects with positive antibody tests are invited to participate in further studies.