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The official name of this gene is “molybdenum cofactor synthesis 2.”
MOCS2 is the gene's official symbol. The MOCS2 gene is also known by other names, listed below.
The MOCS2 gene provides instructions for making two different proteins, MOCS2A and MOCS2B, which combine to form an enzyme called molybdopterin synthase. Molybdopterin synthase performs the second of a series of reactions in the formation (biosynthesis) of a molecule called molybdenum cofactor. Molybdenum cofactor, which contains the element molybdenum, is essential to the function of several enzymes called sulfite oxidase, aldehyde oxidase, xanthine dehydrogenase, and mitochondrial amidoxime reducing component (mARC). These enzymes help break down (metabolize) different substances in the body, some of which are toxic if not metabolized.
MOCS2 gene mutations cause a disorder called molybdenum cofactor deficiency. This disorder is characterized by seizures that begin early in life and brain dysfunction that worsens over time (encephalopathy); the condition is usually fatal by early childhood. At least a dozen mutations in the MOCS2 gene have been found to cause a form of the disorder designated type B or complementation group B.
The MOCS2 gene mutations involved in molybdenum cofactor deficiency likely eliminate the function of MOCS2A, MOCS2B, or both, although in rare cases that are less severe, some protein function may remain. Without either piece of molybdopterin synthase, molybdenum cofactor biosynthesis is impaired. Loss of the cofactor impedes the function of the metabolic enzymes that rely on it.
The resulting loss of enzyme activity leads to buildup of certain chemicals, including sulfite, S-sulfocysteine, xanthine, and hypoxanthine, and low levels of another chemical called uric acid. (Testing for these chemicals can help in the diagnosis of this condition.) Sulfite, which is normally broken down by sulfite oxidase, is toxic, especially to the brain. Researchers suggest that damage caused by the abnormally high levels of sulfite (and possibly other chemicals) leads to encephalopathy, seizures, and the other features of molybdenum cofactor deficiency.
Cytogenetic Location: 5q11
Molecular Location on chromosome 5: base pairs 53,095,678 to 53,109,771
The MOCS2 gene is located on the long (q) arm of chromosome 5 at position 11.
More precisely, the MOCS2 gene is located from base pair 53,095,678 to base pair 53,109,771 on chromosome 5.
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 MOCS2 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.
aldehyde ; carrier ; catalytic ; cofactor ; deficiency ; dehydrogenase ; diagnosis ; encephalopathy ; enzyme ; gene ; molecule ; oxidase ; protein ; subunit ; synthesis ; toxic ; uric acid
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.