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The official name of this gene is “phosphomannomutase 2.”
PMM2 is the gene's official symbol. The PMM2 gene is also known by other names, listed below.
The PMM2 gene provides instructions for making an enzyme called phosphomannomutase (PMM). This enzyme is involved in a process called glycosylation, which attaches groups of sugar molecules (oligosaccharides) to proteins. Oligosaccharides are made up of many small sugar molecules that are attached to one another in a long chain. Glycosylation modifies proteins so they can perform a wider variety of functions. In one of the early steps of glycosylation, the PMM enzyme converts a molecule called mannose-6-phosphate to mannose-1-phosphate. Subsequently, mannose-1-phosphate is converted into GDP-mannose, which can transfer its small sugar molecule called mannose to the growing oligosaccharide chain. Once the correct number of small sugar molecules are linked together to form the oligosaccharide, it can be attached to a protein.
More than 100 mutations in the PMM2 gene have been found to cause congenital disorder of glycosylation type Ia (CDG-Ia). These mutations change the structure of the PMM enzyme in different ways; however, all of the mutations appear to result in reduced enzyme activity. Decreased activity of the PMM enzyme leads to a shortage of GDP-mannose within cells. As a result, there is not enough activated mannose to form oligosaccharides. Glycosylation cannot proceed normally because incorrect oligosaccharides are produced. The signs and symptoms in CDG-Ia are likely due to the production of abnormally glycosylated proteins in many organs and tissues.
Cytogenetic Location: 16p13
Molecular Location on chromosome 16: base pairs 8,797,812 to 8,855,196
The PMM2 gene is located on the short (p) arm of chromosome 16 at position 13.
More precisely, the PMM2 gene is located from base pair 8,797,812 to base pair 8,855,196 on chromosome 16.
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 PMM2 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.
congenital ; enzyme ; gene ; glycosylation ; mannose ; molecule ; oligosaccharides ; phosphate ; protein
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.