Reviewed September 2010
What is the official name of the PYGL gene?
The official name of this gene is “phosphorylase, glycogen, liver.”
PYGL is the gene's official symbol. The PYGL gene is also known by other names, listed below.
What is the normal function of the PYGL gene?
The PYGL gene provides instructions for making an enzyme called liver glycogen phosphorylase. This enzyme breaks down a complex sugar called glycogen. Liver glycogen phosphorylase is one of three related enzymes that break down glycogen in cells; the other glycogen phosphorylases are found in the brain and in muscles. Liver glycogen phosphorylase is found only in liver cells, where it breaks down glycogen into a type of sugar called glucose-1-phosphate. Additional steps convert glucose-1-phosphate into glucose, a simple sugar that is the main energy source for most cells in the body.
How are changes in the PYGL gene related to health conditions?
- glycogen storage disease type VI - caused by mutations in the PYGL gene
At least 17 mutations in the PYGL gene have been found to cause glycogen storage disease type VI (GSDVI). Most mutations change single protein building blocks (amino acids) in liver glycogen phosphorylase, affecting the normal function of the enzyme. In the Old Order Mennonite population, a common mutation (written as 1620+1G>A) disrupts the way the PYGL gene's instructions are used to make the enzyme. A defective liver glycogen phosphorylase enzyme impairs the normal breakdown of glycogen. As a result, liver cells cannot use glycogen for energy, so liver function becomes impaired. A lack of glycogen breakdown within liver cells leads to the major features of GSDVI.
Where is the PYGL gene located?
Cytogenetic Location: 14q21-q22
Molecular Location on chromosome 14: base pairs 50,905,217 to 50,944,530
(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (http://www.ncbi.nlm.nih.gov/gene/5836))
The PYGL gene is located on the long (q) arm of chromosome 14 between positions 21 and 22.
More precisely, the PYGL gene is located from base pair 50,905,217 to base pair 50,944,530 on chromosome 14.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
Where can I find additional information about PYGL?
You and your healthcare professional may find the following resources about PYGL helpful.
Educational resources - Information pages
- Biochemistry (fifth edition, 2002): Glucose Regulation of Liver Glycogen Metabolism (http://www.ncbi.nlm.nih.gov/books/NBK22444/?rendertype=figure&id=A2963)
- Biochemistry (fifth edition, 2002): Glycogen Metabolism in the Liver Regulates the Blood-Glucose Level (http://www.ncbi.nlm.nih.gov/books/NBK22444/)
- Biochemistry (fifth edition, 2002): Phosphorylase Catalyzes the Phosphorolytic Cleavage of Glycogen to Release Glucose 1-phosphate (http://www.ncbi.nlm.nih.gov/books/NBK22467/)
- Gene Reviews - Clinical summary (http://www.ncbi.nlm.nih.gov/books/NBK5941)
Genetic Testing Registry - Repository of genetic test information
- GTR: Genetic tests for PYGL (http://www.ncbi.nlm.nih.gov/gtr/tests/?term=5836%5Bgeneid%5D)
You may also be interested in these resources, which are designed for genetics professionals and researchers.
- PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/pubmed?term=%28PYGL%5BTIAB%5D%29%20OR%20%28glycogen%20phosphorylase%20liver%5BALL%5D%29%20AND%20%28%28Genes%5BMH%5D%29%20OR%20%28Genetic%20Phenomena%5BMH%5D%29%29%20AND%20english%5Bla%5D%20AND%20human%5Bmh%5D%20AND%20%22last%203600%20days%22%5Bdp%5D)
- OMIM - Genetic disorder catalog (http://omim.org/entry/613741)
Research Resources - Tools for researchers
- HGNC Gene Family: Phosphorylases, glycogen (http://www.genenames.org/cgi-bin/genefamilies/set/437)
- HGNC Gene Symbol Report (http://www.genenames.org/cgi-bin/gene_symbol_report?q=data/hgnc_data.php&hgnc_id=9725)
- NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/5836)
What other names do people use for the PYGL gene or gene products?
- glycogen phosphorylase, liver form
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
What glossary definitions help with understanding PYGL?
You may find definitions for these and many other terms in the Genetics Home Reference
- Beauchamp NJ, Taybert J, Champion MP, Layet V, Heinz-Erian P, Dalton A, Tanner MS, Pronicka E, Sharrard MJ. High frequency of missense mutations in glycogen storage disease type VI. J Inherit Metab Dis. 2007 Oct;30(5):722-34. Epub 2007 Aug 21. (http://www.ncbi.nlm.nih.gov/pubmed/17705025?dopt=Abstract)
- Burwinkel B, Bakker HD, Herschkovitz E, Moses SW, Shin YS, Kilimann MW. Mutations in the liver glycogen phosphorylase gene (PYGL) underlying glycogenosis type VI. Am J Hum Genet. 1998 Apr;62(4):785-91. (http://www.ncbi.nlm.nih.gov/pubmed/9529348?dopt=Abstract)
- Chang S, Rosenberg MJ, Morton H, Francomano CA, Biesecker LG. Identification of a mutation in liver glycogen phosphorylase in glycogen storage disease type VI. Hum Mol Genet. 1998 May;7(5):865-70. (http://www.ncbi.nlm.nih.gov/pubmed/9536091?dopt=Abstract)
- Gene Review: Glycogen Storage Disease Type VI (http://www.ncbi.nlm.nih.gov/books/NBK5941)
- NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/5836)
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
See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.