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The official name of this gene is “molybdenum cofactor synthesis 1.”
MOCS1 is the gene's official symbol. The MOCS1 gene is also known by other names, listed below.
The MOCS1 gene provides instructions for making two different proteins, MOCS1A and MOCS1B. Both are involved in the formation (biosynthesis) of a molecule called molybdenum cofactor. Specifically, MOCS1A and MOCS1B perform the first of a series of reactions that produce the cofactor, although the function of MOCS1B in this process is not understood. 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.
MOCS1 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 32 mutations in the MOCS1 gene have been found to cause a form of the disorder designated type A or complementation group A. This is the most common form of the condition, accounting for approximately two-thirds of cases.
The MOCS1 gene mutations involved in molybdenum cofactor deficiency likely eliminate the function of MOCS1A, MOCS1B, or both, although in rare cases that are less severe, some protein function may remain. Without the activity of one or both of these proteins, 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: 6p21.3
Molecular Location on chromosome 6: base pairs 39,904,257 to 39,934,550
The MOCS1 gene is located on the short (p) arm of chromosome 6 at position 21.3.
More precisely, the MOCS1 gene is located from base pair 39,904,257 to base pair 39,934,550 on chromosome 6.
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 MOCS1 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 ; cell ; cofactor ; deficiency ; dehydrogenase ; diagnosis ; encephalopathy ; enzyme ; gene ; molecule ; oxidase ; protein ; synthesis ; toxic ; uric acid
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://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.