2070 – CentAK® anti-GAD65 M

MEDIPAN CentAK® anti-GAD65 M is a radioligand assay used for the determination of autoantibodies to GAD₆₅ for the diagnosis of autoimmune Diabetes mellitus type 1.

Genetic susceptibility and exposure to environmental factors are probable causes of type 1 diabetes, alternatively referred to as insulin-dependent diabetes mellitus (IDDM), a chronic autoimmune destruction of the insulin-secreting pancreatic beta cells. This condition is believed to be completely asymptomatic until about 80-90% of the cells are destroyed, a process that may take years to complete, occurring regardless of age.

Circulating autoantibodies to beta cell antigens are characteristic of the preclinical phase of the autoimmune process. These autoantibodies, especially anti-glutamic acid decarboxylase (GAD), anti-insulin (IAA), and anti-tyrosine phosphatase ICA 512 (IA2), are present several years prior to appearance of clinical symptoms.

Autoantibodies to GAD, the enzyme that catalyses glutamate to GABA conversion, with two isoforms, GAD₆₅ (65 kDa molecular weight) and GAD₆₇ (67 kDa molecular weight), are found in type 1 diabetes and in Stiff-man syndrome (SMS), a rare neurological disorder. The GAD autoantibodies profile in the two diseases differs in their preference to the conformational epitopes, wherein GAD₆₅ autoantibodies are present in 70-80% of newly diagnosed patients with type 1 diabetes.

An essential part of the risk assessment of type 1 diabetes in children and adolescent includes a combination of the autoantibodies to GAD₆₅ and IA2, offering a more sensitive and predictive method than ICA in risk groups, e.g. relatives of type 1 diabetes patients. GAD₆₅ is also important in the diagnosis of type 2 diabetes adults with pronounced hyperglcemia where the patients become insulin dependent several months to years after therapy with oral hypoglycemic agents. Such patients are thought to have latent autoimmune diabetes in adults, a slowly progressive form of type 1 diabetes. GAD₆₅ detection in this kind of patients provides a sensitive and specific diagnostic evidence for future dependence on insulin.