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LGIC gene family
Reviewed June 2012
What are the LGIC genes?
Genes in the LGIC gene family provide instructions for making ligand-gated ion channels. These channels span the membrane that surrounds cells and form a hole (pore) through which positively or negatively charged atoms (ions), such as sodium, potassium, calcium, or chloride ions, can flow. The flow of ions is triggered by the attachment (binding) of proteins called ligands. Each channel is "opened" by the binding of a particular ligand. The ligands that open ligand-gated ion channels are called neurotransmitters because they transmit signals in the brain.
Genes in the LGIC family can be divided into several groups based on the ligand that binds to the channel. Nicotinic acetylcholine receptors are triggered by the binding of a chemical called acetylcholine. Serotonin type 3 (5-HT3) receptors are triggered by serotonin. GABAA receptors are triggered by gamma-aminobutyric acid (GABA). Ionotropic glutamate receptors are triggered by glutamate. Glycine receptors are triggered by glycine. Ionotropic purinergic receptors are triggered by a chemical called adenosine triphosphate (ATP). And zinc-activated channels are triggered by zinc.
Ligand-gated ion channels play an important role in the nervous system. The channels are primarily found in nerve cells (neurons) in the brain, spinal cord, and muscles, and they function to control the transmission of nerve impulses from neuron to neuron or neuron to muscle. The flow of positively charged ions into the cell turns on (excites) nerve impulses. In contrast, the flow of negatively charged ions into the cell blocks (inhibits) nerve impulses to prevent the nervous system from being overloaded with too many signals. Nicotinic acetylcholine receptors, 5-HT3 receptors, and ionotropic glutamate receptors allow the flow of positively charged sodium, potassium, and, sometimes, calcium ions, which excites nerve signaling. Similarly, ionotropic purinergic receptors allow calcium ions to cross the cell membrane, exciting nerve signaling. GABAA and glycine receptors allow the flow of negatively charged chloride ions, and so these channels inhibit nerve signaling. The function of zinc channels is unknown.
Signaling in the brain through ligand-gated ion channels is important for many neurological functions, including learning, memory formation, movement of muscles, and reflexes. Mutations in genes in the LGIC family can lead to neurological disorders such as seizures, movement difficulties, and abnormal muscle stiffness and weakness.
Which genes are included in the LGIC gene family?
The HUGO Gene Nomenclature Committee (HGNC) provides a list of genes in the LGIC
Genetics Home Reference summarizes the normal function and health implications of this member of the LGIC gene family: GABRA1.
What conditions are related to genes in the LGIC gene family?
Genetics Home Reference includes these conditions related to genes in the LGIC gene family:
Where can I find additional information about the LGIC gene family?
You may find the following resources about the LGIC gene family helpful.
Where can I find general information about genes and gene families?
The Handbook provides basic information about genetics in clear language.
What glossary definitions help with understanding the LGIC gene family?
acetylcholine ; adenosine triphosphate ; ATP ; calcium ; cell ; cell membrane ; channel ; chloride ; GABA ; gamma-aminobutyric acid ; gene ; glycine ; HT ; ions ; ligand ; nervous system ; neurological ; neuron ; neurotransmitters ; potassium ; receptor ; sodium
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (5 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.