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The official name of this gene is “ATPase, Cu++ transporting, alpha polypeptide.”
ATP7A is the gene's official symbol. The ATP7A gene is also known by other names, listed below.
The ATP7A gene provides instructions for making a protein that is important for regulating copper levels in the body. Copper is necessary for many cellular functions, but it is toxic when present in excessive amounts. The ATP7A protein is found throughout the body, except in liver cells. In the small intestine, this protein helps control the absorption of copper from food. In other cells, the ATP7A protein has a dual role and shuttles between two cellular locations. The protein normally resides in a cell structure called the Golgi apparatus, which modifies newly produced proteins, including enzymes. In the Golgi apparatus, the ATP7A protein supplies copper to certain enzymes that are critical for the structure and function of bone, skin, hair, blood vessels, and the nervous system. If copper levels in the cell environment are elevated, however, the ATP7A protein moves to the cell membrane and eliminates excess copper from the cell.
The ATP7A gene belongs to a family of genes called ATP (ATPase superfamily).
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.
Several mutations in the ATP7A gene are responsible for a condition called occipital horn syndrome or X-linked cutis laxa, which is considered a mild form of Menkes syndrome. Occipital horn syndrome is characterized by loose and sagging skin, wedge-shaped calcium deposits in a bone at the base of the skull (the occipital bone), coarse hair, and loose joints.
Most of the mutations that cause occipital horn syndrome reduce but do not eliminate the production of the ATP7A protein. A shortage of this protein impairs the absorption of copper from food and prevents its normal distribution to cells throughout the body. The decreased supply of copper can reduce the activity of numerous copper-containing enzymes, affecting the structure and function of bone, skin, hair, blood vessels, and the nervous system. The reduced activity of these enzymes underlies the characteristic features of occipital horn syndrome.
Researchers have identified more than 150 mutations in the ATP7A gene that cause Menkes syndrome. Many of these mutations delete part of the gene and likely result in a shortened ATP7A protein. Other mutations insert additional DNA building blocks (nucleotides) into the gene or change single nucleotides. All of these mutations prevent the production of functional ATP7A protein. As a result, the absorption of copper from food is impaired, and copper is not supplied to certain enzymes. The abnormal protein may get stuck in the cell membrane and become unable to shuttle back and forth from the Golgi apparatus.
The disrupted activity of the ATP7A protein causes copper to be poorly distributed to cells in the body. Copper accumulates in some tissues, such as the small intestine and kidneys, while the brain and other tissues have unusually low levels. The decreased supply of copper can reduce the activity of numerous copper-containing enzymes, affecting the structure and function of bone, skin, hair, blood vessels, and the nervous system. The signs and symptoms of Menkes syndrome are caused by the reduced activity of these copper-containing enzymes.
Cytogenetic Location: Xq21.1
Molecular Location on the X chromosome: base pairs 77,166,193 to 77,305,891
The ATP7A gene is located on the long (q) arm of the X chromosome at position 21.1.
More precisely, the ATP7A gene is located from base pair 77,166,193 to base pair 77,305,891 on the X chromosome.
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 ATP7A 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.
calcium ; cell ; cell membrane ; DNA ; gene ; Golgi apparatus ; intestine ; nervous system ; protein ; syndrome ; toxic
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/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.