Update on inherited disorders of GABA metabolism

Abstract

γ-aminobutyric acid (GABA) serves as the main inhibitory cortical neurotransmitter and is involved in crucial functions of neural circuitry affecting cognition, communication, movement, behavior, and the seizure threshold. GABAergic neurons and interneurons contribute to essential aspects of cortical dynamic organization and regulatory processes and mediate aspects of synaptic development. Inherited metabolic disorders affecting the metabolic pathways of GABA, its transport, and its receptors lead to a wide array of neurodevelopmental manifestations. Presentation typically ensues at early ages but could occur later in life and range in severity. This group of disorders warrants increased suspicion, as their early identification and management may lead to clinical improvement and shorten the diagnostic odyssey often associated with affected individuals. We provide an overview of the scientific basis, clinical presentation, and ongoing therapeutic advances of the main disorders of GABA metabolism stemming from deficiencies of succinic semialdehyde dehydrogenase (SSADH), GABA-transaminase, GABA transporter, and GABA receptor subunits.