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The official name of this gene is “phosphatidylinositol glycan anchor biosynthesis, class V.”
PIGV is the gene's official symbol. The PIGV gene is also known by other names, listed below.
The PIGV gene provides instructions for making an enzyme called GPI mannosyltransferase 2. This enzyme takes part in a series of steps that produce a molecule called a glycosylphosphosphatidylinositol (GPI) anchor. Specifically, GPI mannosyltransferase 2 adds the second of three molecules of a complex sugar called mannose to the GPI anchor. This step takes place in the endoplasmic reticulum, which is a structure involved in protein processing and transport within cells. The complete GPI anchor attaches (binds) to various proteins in the endoplasmic reticulum. After the anchor and protein are bound, the anchor attaches itself to the outer surface of the cell membrane, ensuring that the protein will be available when it is needed.
The PIGV gene belongs to a family of genes called dolichyl D-mannosyl phosphate dependent mannosyltransferases (dolichyl D-mannosyl phosphate dependent mannosyltransferases). It also belongs to a family of genes called PIG (phosphatidylinositol glycan anchor biosynthesis).
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 14 mutations in the PIGV gene have been found to cause Mabry syndrome, a condition characterized by intellectual disability, distinctive facial features, increased levels of an enzyme called alkaline phosphatase in the blood (hyperphosphatasia), and other signs and symptoms. These mutations change single protein building blocks (amino acids) in the GPI mannosyltransferase 2 enzyme. The altered protein is less able to add mannose to the forming GPI anchor. The incomplete GPI anchor cannot attach to proteins; without the anchor, the proteins cannot bind to the cell membrane and are released from the cell.
An enzyme called alkaline phosphatase is normally attached to a GPI anchor. However, when the anchor is impaired, alkaline phosphatase cannot be anchored to the cell membrane. Instead, alkaline phosphatase is released from the cell. This abnormal release of alkaline phosphatase is responsible for the hyperphosphatasia in Mabry syndrome. It is unclear how PIGV gene mutations lead to the other features of Mabry syndrome, but these signs and symptoms are likely due to a lack of proper GPI anchoring of proteins to cell membranes.
Cytogenetic Location: 1p36.11
Molecular Location on chromosome 1: base pairs 27,113,738 to 27,124,893
The PIGV gene is located on the short (p) arm of chromosome 1 at position 36.11.
More precisely, the PIGV gene is located from base pair 27,113,738 to base pair 27,124,893 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 PIGV 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 ; cell ; cell membrane ; class ; endoplasmic reticulum ; enzyme ; gene ; mannose ; molecule ; phosphatase ; protein ; syndrome
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.