Glutamic acid decarboxylase

Glutamic acid decarboxylase (GAD) is an enzyme that catalyses the conversion of glutamic acid to gamma-aminobutyric acid (GABA), a key inhibitory neurotransmitter in the central nervous system. Its clinical significance lies in its association with autoimmune conditions, particularly type 1 diabetes and certain neurological disorders, where antibodies against GAD can disrupt normal function. A notable complication is the development of stiff-person syndrome, characterised by muscle stiffness and spasms.