glutamate decarboxylase

(redirected from GAD antibodies)

glu·ta·mate de·car·box·yl·ase (GAD),

a carboxy-lyase converting l-glutamate to 4-aminobutyrate and CO2 as well as l-aspartate to 3-aminopropanoate and CO2; a defect in the binding of this protein's coenzyme is believed to cause pyridoxine dependency with seizures.


An intronless gene on chromosome 1q31 that encodes a glutamine synthetase, which catalyses the synthesis of glutamine from glutamate and ammonia. Glutamine is a key source of energy and is involved in cell proliferation, inhibition of apoptosis, and cell signalling. GLUL is expressed during early foetal stages, and plays an important role in controlling pH by removing ammonia from circulation.

Molecular pathology
GLUL mutations are associated with congenital glutamine deficiency.
References in periodicals archive ?
Markedly elevated GAD antibodies in SPS: Effects of age and illness duration.
Another 6% had steroid-associated diabetes; 4% had diabetes secondary to pancreatitis; 3% were positive for GAD antibodies showing they had latent autoimmune diabetes of adulthood (LADA); and a small number of patients had rare disorders.
However, anti GAD antibodies has been found positive in few studies in relation to therapy resistant forms of epilepsy.
Clinical and genetic characteristics of type 2 diabetes with and without GAD antibodies.
If type 1 diabetes is suspected on clinical grounds, or if ICA or GAD antibodies are positive, the patient should be presumed to have type 1 diabetes and should be treated with insulin replacement therapy.
Previously, it has been demonstrated that the GAD antibody frequency in mixed connective tissue disease and stiff-man syndrome is increased, although not all patients who suffer from these diseases and are positive for GAD antibodies develop type-1 diabetes (13,14).
In addition, thresholds for positivity for GAD antibodies have generally been defined in children.
The frequencies of positive results for GAD antibodies and the concentrations of GAD antibodies were established in a population of 1403 schoolchildren, ages 10-12 years, without chronic diseases (17).
Forty-three serum samples from 38 cystic fibrosis patients (collected in 1990-1992) were analyzed for GAD antibodies.
Sera were tested for GAD antibodies by radiobinding assay (RBA) (13) or immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the Triton X-100 fraction of [[35.
One was positive for GAD antibodies in a sample taken before diabetes onset (at the presenting seizure) and 7 months after onset of diabetes (13-month epilepsy duration).