What does GAD mean in CLINICAL MEDICINE

GAD is an enzyme that converts glutamic acid into gamma-aminobutyric acid (GABA), a neurotransmitter that inhibits nerve impulses in the brain. GAD is crucial for maintaining a balance of excitatory and inhibitory signals in the nervous system.

GAD is the rate-limiting enzyme in GABA synthesis. It catalyzes the irreversible decarboxylation of glutamic acid, producing GABA and carbon dioxide. This process plays a vital role in regulating neuronal excitability and maintaining synaptic balance.

There are two main isoforms of GAD in the brain:

• GAD65 (65 kDa) is predominantly found in the axon terminals of GABAergic neurons and is responsible for the synthesis of GABA released into the synaptic cleft.
• GAD67 (67 kDa) is primarily located in the cell bodies of GABAergic neurons and contributes to the synthesis of GABA used for neuronal metabolism.

Impaired GAD activity can lead to a deficiency of GABA, resulting in a hyperexcitable state in the nervous system. This imbalance can contribute to various neurological disorders, including epilepsy, anxiety, and autism spectrum disorders.

GAD activity can be affected by several factors, such as:

• Genetic mutations
• Nutritional deficiencies (e.g., vitamin B6)
• Certain medications
• Environmental toxins
• Stress