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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed January 2008

What is the official name of the GALE gene?

The official name of this gene is “UDP-galactose-4-epimerase.”

GALE is the gene's official symbol. The GALE gene is also known by other names, listed below.

What is the normal function of the GALE gene?

The GALE gene provides instructions for making an enzyme called UDP-galactose-4-epimerase. This enzyme enables the body to process a simple sugar called galactose, which is present in small amounts in many foods. Galactose is primarily part of a larger sugar called lactose, which is found in all dairy products and many baby formulas.

UDP-galactose-4-epimerase converts a modified form of galactose (UDP-galactose) to another modified sugar (UDP-glucose). Glucose is a simple sugar that is the main energy source for most cells. This enzyme also promotes the reverse chemical reaction, the conversion of UDP-glucose to UDP-galactose. UDP-galactose is used to build galactose-containing proteins and fats, which play critical roles in chemical signaling, building cellular structures, transporting molecules, and producing energy.

Does the GALE gene share characteristics with other genes?

The GALE gene belongs to a family of genes called SDR (short chain dehydrogenase/reductase superfamily).

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? ( in the Handbook.

How are changes in the GALE gene related to health conditions?

galactosemia - caused by mutations in the GALE gene

More than 20 mutations in the GALE gene have been identified in people with a form of galactosemia known as type III or galactose epimerase deficiency. Most of these genetic changes alter a single protein building block (amino acid) in UDP-galactose-4-epimerase, which makes the enzyme unstable or disrupts its usual function.

Some GALE mutations severely reduce or eliminate the activity of UDP-galactose-4-epimerase in all of the body's tissues. These genetic changes lead to a severe form of galactosemia type III described as the generalized form. A loss of enzyme activity prevents cells from processing galactose obtained from the diet. As a result, compounds associated with galactose processing can build up to toxic levels in the body. The accumulation of these substances damages tissues and organs, leading to serious complications such as clouding of the lens of the eye (cataract), intellectual disability, and damage to the liver, kidneys, and brain.

Other mutations in the GALE gene reduce the activity of UDP-galactose-4-epimerase in red blood cells only. These genetic changes underlie a much milder form of galactosemia type III described as the peripheral form. Affected individuals may not have any of the complications typically associated with galactosemia and often do not require treatment. Researchers are unclear why the effects of some GALE mutations are restricted to blood cells, while other mutations affect all of the body's tissues and cause severe medical problems.

Where is the GALE gene located?

Cytogenetic Location: 1p36-p35

Molecular Location on chromosome 1: base pairs 23,795,598 to 23,800,803

The GALE gene is located on the short (p) arm of chromosome 1 between positions 36 and 35.

The GALE gene is located on the short (p) arm of chromosome 1 between positions 36 and 35.

More precisely, the GALE gene is located from base pair 23,795,598 to base pair 23,800,803 on chromosome 1.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about GALE?

You and your healthcare professional may find the following resources about GALE helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the GALE gene or gene products?

  • galactowaldenase
  • SDR1E1
  • UDP Galactose Epimerase
  • UDP-Glucose 4-Epimerase
  • UDP - Uridyl diphosphate galactose-4-epimerase
  • Uridine diphosphate galactose-4-epimerase
  • Uridine Diphosphate Glucose Epimerase

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding GALE?

amino acid ; cataract ; deficiency ; disability ; enzyme ; galactose ; gene ; glucose ; glycolipid ; peripheral ; protein ; simple sugar ; toxic

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (


  • Henderson JM, Huguenin SM, Cowan TM, Fridovich-Keil JL. A PCR-based method for detecting known mutations in the human UDP galactose-4'-epimerase gene associated with epimerase-deficiency galactosemia. Clin Genet. 2001 Nov;60(5):350-5. (
  • Holden HM, Rayment I, Thoden JB. Structure and function of enzymes of the Leloir pathway for galactose metabolism. J Biol Chem. 2003 Nov 7;278(45):43885-8. Epub 2003 Aug 15. Review. (
  • Leslie ND. Insights into the pathogenesis of galactosemia. Annu Rev Nutr. 2003;23:59-80. Epub 2003 Apr 9. Review. (
  • NCBI Gene (
  • Novelli G, Reichardt JK. Molecular basis of disorders of human galactose metabolism: past, present, and future. Mol Genet Metab. 2000 Sep-Oct;71(1-2):62-5. Review. (
  • Schulz JM, Watson AL, Sanders R, Ross KL, Thoden JB, Holden HM, Fridovich-Keil JL. Determinants of function and substrate specificity in human UDP-galactose 4'-epimerase. J Biol Chem. 2004 Jul 30;279(31):32796-803. Epub 2004 Jun 2. (
  • Timson DJ. Functional analysis of disease-causing mutations in human UDP-galactose 4-epimerase. FEBS J. 2005 Dec;272(23):6170-7. (
  • Timson DJ. The structural and molecular biology of type III galactosemia. IUBMB Life. 2006 Feb;58(2):83-9. Review. (


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? ( in the Handbook.

Reviewed: January 2008
Published: March 30, 2015