|http://ghr.nlm.nih.gov/ A service of the U.S. National Library of Medicine®|
The official name of this gene is “ALG6, alpha-1,3-glucosyltransferase.”
ALG6 is the gene's official symbol. The ALG6 gene is also known by other names, listed below.
The ALG6 gene provides instructions for making an enzyme that is involved in a process called glycosylation. Glycosylation is a process by which sugar molecules (oligosaccharides) are attached to proteins and fats. Oligosaccharides are made up of many sugar molecules that are attached to one another in a stepwise process forming a complex chain. Glycosylation modifies proteins so they can perform a wider variety of functions. The enzyme produced from the ALG6 gene transfers a simple sugar called glucose to the growing oligosaccharide. Once the correct number of sugar molecules are linked together, the oligosaccharide is attached to a protein or fat.
At least 20 mutations in the ALG6 gene have been found to cause congenital disorder of glycosylation type Ic (known as ALG6-CDG). This condition typically leads to developmental delay, vision problems, seizures, and other signs and symptoms. Mutations in the ALG6 gene result in the production of an abnormal enzyme with reduced or no activity. A common mutation replaces the protein building block (amino acid) alanine with the amino acid valine at position 333 in the enzyme. This mutation, written as Ala333Val or A333V, results in an enzyme with reduced activity. Without a properly functioning enzyme, glycosylation cannot proceed normally, and oligosaccharides are incomplete. As a result, glycosylation is reduced or absent. The wide variety of signs and symptoms in ALG6-CDG are likely due to impaired glycosylation of proteins and fats that are needed for normal function in many organs and tissues, including the brain, eyes, and hormone-producing (endocrine) system.
Cytogenetic Location: 1p31.3
Molecular Location on chromosome 1: base pairs 63,367,589 to 63,438,561
The ALG6 gene is located on the short (p) arm of chromosome 1 at position 31.3.
More precisely, the ALG6 gene is located from base pair 63,367,589 to base pair 63,438,561 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 ALG6 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.
alanine ; amino acid ; asparagine ; congenital ; developmental delay ; enzyme ; gene ; glucose ; glycosylation ; hormone ; mutation ; oligosaccharides ; precursor ; protein ; simple sugar ; valine
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.