|http://ghr.nlm.nih.gov/ A service of the U.S. National Library of Medicine®|
The official name of this gene is “ATPase, Na+/K+ transporting, alpha 2 polypeptide.”
ATP1A2 is the gene's official symbol. The ATP1A2 gene is also known by other names, listed below.
The ATP1A2 gene provides instructions for making one part (the alpha-2 subunit) of a protein known as a Na+/K+ ATPase. This protein uses energy from a molecule called adenosine triphosphate (ATP) to transport charged atoms (ions) into and out of cells. Specifically, it pumps sodium ions (Na+) out of cells and potassium ions (K+) into cells.
Na+/K+ ATPases that include the alpha-2 subunit are primarily found in nervous system cells called glia, which protect and maintain nerve cells (neurons). Through its action in glia, the protein plays a critical role in the normal function of neurons. Communication between neurons depends on chemicals called neurotransmitters. To relay signals, a neuron releases neurotransmitters, which attach to receptor proteins on neighboring neurons. After the neurotransmitters have had their effect, they detach from their receptors and are removed from the spaces between neurons by glia. This process is carefully regulated to ensure that signals are transmitted accurately throughout the nervous system. The Na+/K+ ATPase helps regulate this process by stimulating glia to clear neurotransmitters from the spaces between neurons. This protein also removes excess potassium ions from these spaces.
The ATP1A2 gene belongs to a family of genes called ATP (ATPases).
A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.
At least one mutation in the ATP1A2 gene can cause alternating hemiplegia of childhood. The primary feature of this condition is recurrent episodes of temporary paralysis, often affecting one side of the body (hemiplegia). During some episodes, the paralysis alternates from one side to the other or affects both sides of the body at the same time. The known ATP1A2 gene mutation associated with this condition replaces a single protein building block (amino acid) in Na+/K+ ATPase: the amino acid threonine is replaced with the amino acid asparagine at protein position 378 (written as Thr378Asn or T378N). This genetic change probably impairs the protein's ability to transport ions, although it is unclear how the mutation leads to the specific features of alternating hemiplegia of childhood.
More than 30 mutations in the ATP1A2 gene have been identified in people with familial hemiplegic migraine type 2 (FHM2). This condition is characterized by migraine headaches with a pattern of neurological symptoms known as aura. In FHM2, the aura includes temporary numbness or weakness on one side of the body (hemiparesis). Most of the mutations involved in FHM2 change single amino acids in the Na+/K+ ATPase protein. Some mutations impair the protein's ability to transport ions. Others prevent the production of any protein from one copy of the ATP1A2 gene in each cell. As a result, less potassium is pumped into neurons, less sodium is pumped out of these cells, and neurotransmitters spend more time in the spaces between neurons. The resulting changes in signaling in the brain lead people with FHM2 to develop these severe headaches.
ATP1A2 gene mutations can also cause sporadic hemiplegic migraine. The signs and symptoms of this condition are identical to those of FHM2 (described above); however, sporadic hemiplegic migraine occurs in people with no family history of the condition. As in FHM2, most of the mutations associated with sporadic hemiplegic migraine change single amino acids in the Na+/K+ ATPase protein. These changes impair the function of the protein. Although the mutations that cause sporadic hemiplegic migraine are not as well-studied as those in familial hemiplegic migraine, it is thought that they have similar effects: impairing the transport of sodium and potassium ions and prolonging the presence of neurotransmitters between neurons. The abnormal signaling resulting from these changes leads to the headaches and auras characteristic of the condition.
Cytogenetic Location: 1q23.2
Molecular Location on chromosome 1: base pairs 160,115,730 to 160,143,591
The ATP1A2 gene is located on the long (q) arm of chromosome 1 at position 23.2.
More precisely, the ATP1A2 gene is located from base pair 160,115,730 to base pair 160,143,591 on chromosome 1.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about ATP1A2 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
acids ; adenosine triphosphate ; amino acid ; asparagine ; ATP ; aura ; catalytic ; cell ; depression ; familial ; family history ; gene ; glia ; hemiparesis ; hemiplegia ; hemiplegic ; ions ; migraine ; molecule ; mutation ; Na ; nervous system ; neurological ; neuron ; neurotransmitters ; potassium ; protein ; receptor ; sodium ; sporadic ; subunit ; threonine
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.