In type 1 diabetic patients, we found the INS mutation c.163C>T (R55C) in a girl who at 10 years of age presented with ketoacidosis and insulin-dependent, GAD, and insulinoma-associated antigen-2 (IA-2) antibody-negative diabetes.
GAD positive (n=8) and GAD negative (n=8) subjects diagnosed with Type 2 diabetes were matched for age, gender, body mass index, duration of diabetes and glycaemic control.
Offspring who were GAD or IA-2 autoantibody positive at birth (n = 678) had significantly lower risks for developing multiple islet autoantibodies (5-year risk 1.3%) and diabetes (8-year risk 1.1%) than offspring who were islet autoantibody negative at birth (5.3%, P = 0.008; and 3%, P = 0.04, respectively).
They focused testing on patients negative for both GAD and islet antigen 2 (IA-2) islet autoantibodies, thereby ruling out those with markers of type 1 diabetes, the most common form of diabetes in this age group.
A potent mouse mAb (GAD6) to GAD65, and a rabbit polyclonal antibody (AB108) to GAD67, were used to standardize the reactivity of the diabetes sera with the mutant molecules.
The low prevalence of anti-GAD antibodies and HLA-DQA1 and DQB1 susceptibility alleles among recent-onset NIDDM patients, which was similar to observations in control subjects, suggests that diabetes in Korean adults is unlikely to have an autoimmune component to its pathogenesis.
We conclude that ICA+ relatives with GAD antibodies or low AIRg have a high risk for development of diabetes, but among ICA+ GAD+ relatives, the addition of IAA or a single determination of AIRg does not enhance the prediction of diabetes.
We measured insulin autoantibodies (IAAs), GAD autoantibodies (GAAs), and ICA512bdc autoantibodies (ICA512bdcAAs) by radioassay, in addition to ICAs, in 882 first-degree relatives of patients with type I diabetes, 50 of whom later developed diabetes with a median follow-up of 2.0 years (maximum 11.3 years).
By immunoprecipitation of recombinant GAD65 and GAD67 protein and protein fragments, 83% of sera from individuals with new-onset diabetes or prediabetes (n = 30) had GAD65 autoantibodies, but only 26% had GAD67 autoantibodies.