There are two forms of Glutamic acid decarboxylase (GAD): GAD65 and GAD67. This ELISA assay detectes autoantibodies to GAD65. Anti-GAD Ab are specific for Type 1 insulin dependent diabetes mellitus (IDDM) and Stiff Persons Syndrome (SPS). GAD protein is most highly expressed in the brain and in the islets of Langerhans. Autoantibodies to GAD are associated with IDDM and Stiff-person syndrome.
Tube
Serum Gel
ID
12792
Availability
Weekdays
Additional information
GAD converts glutamic acid to gamma-aminobutyric acid that is involved in the control of release of insulin from secretory granules. It is not specific for pancreatic beta cells as it is also found in the cerebellum, sympathetic ganglia and testis. 70-80% of newly diagnosed IDDM are positive for anti-GAD antibodies as are 50% of relatives. These antibodies disappear with progression of disease (1-2 yrs). The presence of anti-GAD Ab can confirm the clinical diagnosis of SPS. 60-70% of patients with Stiff-person syndrome have anti-GAD antibodies. Note, as SPS can co-exist with IDDM, false positive results may occur where IDDM is present and the diagnosis of SPS is not clear.
Turn around
14 days
Send to
Leeds General Infirmary
Clinical Immunology
Old Medical School
Great George Street
Leeds
LS1 3EX
Collection Con
No restrictions
Frequency
Every fortnight
Sample REQ
Blood
Ref. Range (Male)
<10
Ref. Range (Female)
<10
Ref. Range (Paed)
<10
Ref. Range Notes
Normal range <10 IU/mL
Units
IU/mL
IP Acute TAT
Contact laboratory
IP Routine TAT
14 days
GP Acute TAT
Contact Laboratory
GP Routine TAT
14 days