Identification of β Cell Dysfunction in Relatives of Individuals With Type 1 Diabetes Mellitus

Inclusion criteria

for each subject group* note age limits different for each group*:

• Nonrelative controls: Male and female adults 18-55 years old with no family history of Type 1 Diabetes, who have tested negative for glutamic acid decarboxylase, microinsulin, islet cell, islet antigen 2, and zinc transporter 8 autoantibodies
• Ab negative FDRs: Male and female adults 18-50 years old with a first degree relative (sibling, child, or parent) with T1D, who have tested negative for the above islet autoantibodies
• Ab + T1D Relatives: Male and females aged 12-50 years old with a first or second degree relative diagnosed with T1D, and testing positive for 1 of the above islet autoantibodies either at the screening visit, or through TrialNet screening obtained within the past 12 months.

Criteria for all subjects:

• BMI≤40 kg/m2 (If FDR is 40 kg/m2, the healthy control BMI can not exceed 45 kg/m2)
• HbA1c< 5.7%
• No medical history of diabetes.

Exclusion criteria

for all participants:

• Any type of diabetes or hyperglycemia (HbA1c≥5.7%)
• Chronic illness or use of medications which interfere with glucose or islet hormone metabolism.
• Hemoglobin < 12 g/dL
• Presence of any psychiatric disorder that will affect the ability to participate in the study
• Pregnancy
• Severe milk or soy allergy that would disallow Boost® ingestion for MMTT
• Any condition that, in the judgment of the investigator, will adversely affect adequate participation in, or the safety or technical performance of the protocol.