Glutamic acid Decarboxylase (GAD) antibodies
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 day |
| 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 |
| Telepath | GAD3L |
| ICE Codes | IGAD |
