Antibodies against glutamic acid decarboxylase, abbreviated as anti-GAD, are an important marker in the diagnosis of type 1 diabetes. Their presence leads to the destruction of pancreatic islets, which are responsible for insulin production, which results in the appearance of diabetes symptoms. The presence of anti-GAD antibodies also accompanies the very rare rigid human syndrome. What does a high level of anti-GAD antibodies mean?
Contents:
- Anti-GAD antibodies - indications for the test
- Anti-GAD antibodies - what is the test and how much does it cost?
- Anti-GAD antibodies - what does high level mean?
Antibodies against glutamic acid decarboxylase , abbreviatedanti-GAD , belong to the group of antibodies involved in the development of type 1 diabetes. Decarboxylase glutamic acid (GAD) is an enzyme located in the brain and pancreas where it performs several important functions. The enzyme is, inter alia, responsible for the production of gamma-aminobutyric acid (GABA) - the main neurotransmitter that silences the nervous system.
Anti-GAD antibodies (specifically against the isoenzyme with a molecular weight of 65, the so-called anti-GAD65) are produced as a result of a chronic autoimmune process that destroys pancreatic beta cells, which are responsible for the production of insulin.
As a result of the successive destruction of the pancreatic islets, the production of insulin stops, the lack of which is responsible for the symptoms of type 1 diabetes and the need to take synthetic inulin.
Other antibodies involved in the development of type 1 diabetes include anti-tyrosine phosphatase (anti-IA-2) and anti-insulin (anti-IAA) antibodies
Anti-GAD antibodies - indications for the test
Anti-GAD antibody testing is primarily used to differentiate type 1 diabetes from type 2 diabetes. This is of particular importance in the diagnosis of late-onset autoimmune diabetes in adults (LADA), which it does not appear until 4-5. a decade of life. It may initially be diagnosed as type 2 diabetes due to the late age of diagnosis. Anti-GAD antibodies are present in 70-80% of people with newly diagnosed type 1 diabetes and persist for many years after diagnosis.
Due to anti-GAD antibodies appearing onmany years before the first symptoms of type 1 diabetes, they can also be helpful in finding people at increased risk of developing type 1 diabetes, especially among relatives of people already suffering from this type of diabetes.
In addition, the presence of anti-GAD antibodies is found in various neurological syndromes such as:
- cerebellar ataxia
- stiff man syndrome
- limbic encephalitis
- convulsions
- eye movement disorder
- Miller-Fisher syndrome
Anti-GAD antibodies - what is the test and how much does it cost?
The anti-GAD antibody test is performed from venous blood taken from the elbow bend. Before the examination, the patient does not need to be fasting. The methods used to determine anti-GAD antibodies are radioimmunoassay or enzyme immunoassay methods, e.g. ELISA.
The quantitative test of GAD anti-GAD antibodies (IgG-type immunoglobulins) in a private laboratory costs about PLN 100.
Anti-GAD antibodies - what does high level mean?
Normal anti-GAD antibody levels are usually between 0 and 10 IU / ml . However, the normal range may differ depending on the diagnostic method used in the laboratory.
Increased levels of anti-GAD antibodies along with the coexistence of diabetes symptoms such as increased blood glucose levels, the presence of glucose and / or ketone bodies in the urine, increased thirst and frequent use of the toilet, weight loss or weakness indicate type 1 diabetes .
Increased levels of anti-GAD antibodies without symptoms of diabetes in the patient, but with autoimmune diseases in his family history, may indicate the initiation of the autoimmune process leading to the development of type 1 diabetes.
High levels of anti-GAD antibodies can also be associated with the rare human rigid syndrome. This syndrome is manifested by constant body stiffness, painful muscle contractions that often occur under the influence of various stimuli (e.g. noise, light).
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Karolina Karabin, MD, PhD, molecular biologist, laboratory diagnostician, Cambridge Diagnostics Polska A biologist by education, specializing in microbiology and diagnosticianlaboratory with over 10 years of experience in laboratory work. A graduate of the College of Molecular Medicine and a member of the Polish Society of Human Genetics. Head of research grants at the Laboratory of Molecular Diagnostics at the Department of Hematology, Oncology and Internal Diseases of the Medical University of Warsaw. She defended the title of doctor of medical sciences in the field of medical biology at the 1st Faculty of Medicine of the Medical University of Warsaw. Author of many scientific and popular science works in the field of laboratory diagnostics, molecular biology and nutrition. On a daily basis, as a specialist in the field of laboratory diagnostics, he runs the content department at Cambridge Diagnostics Polska and cooperates with a team of nutritionists at the CD Dietary Clinic. He shares his practical knowledge on diagnostics and diet therapy of diseases with specialists at conferences, training sessions, and in magazines and websites. She is particularly interested in the influence of modern lifestyle on molecular processes in the body.
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