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Diseases

Genetic and Rare Diseases Information Center (GARD)

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Galactosemia


Other Names for this Disease
  • Galactose-1-phosphate uridyltransferase deficiency
  • Galactosemia, classic
  • GALT deficiency
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Overview



What is galactosemia?

What are the signs and symptoms of galactosemia?

How is galactosemia diagnosed?

How might galactosemia be treated?


What is galactosemia?

Galactosemia, which means “galactose in the blood”, is a rare inherited condition. People with galactosemia have problems digesting a type of sugar called galactose from the food they eat. Because they cannot break galactose down properly, it builds up in their blood. Galactose is found in milk and all foods that contain milk. Galactosemia occurs when an enzyme, called ‘galactose-1-phosphate uridyl transferase’ (GALT), is either missing or not working properly. Without enough GALT enzyme activity, galactose cannot be changed to glucose so it builds up in the blood in large amounts.[1]

There are different types of galactosemia: classic galactosemia (also known as type I and is the most common and most severe form of the condition), galactosemia type II (also called galactokinase deficiency), and type III (also called galactose epimerase deficiency). The different types of galactosemia is caused by mutations in the GALT, GALE, and GALK1 genes and is inherited in an autosomal recessive fashion.[1][2]
Last updated: 6/9/2011

What are the signs and symptoms of galactosemia?

If infants with classic galactosemia are not treated promptly with a low-galactose diet, life-threatening complications appear within a few days after birth. Affected infants typically develop feeding difficulties, diarrhea, vomitting, a lack of energy, failure to thrive, jaundice, liver damage, and bleeding. Other serious complications can include overwhelming bacterial infections (sepsis) and shock. Affected children are also at increased risk of developmental delay, cataract, speech difficulties, and intellectual disability. Females with classic galactosemia may experience reproductive problems caused by ovarian failure.[2]

Galactosemia type II causes fewer medical problems than the classic type. Affected infants may develop cataracts, but otherwise usually experience few long-term complications. The signs and symptoms of galactosemia type III vary from mild to severe and can include cataracts, delayed growth and development, intellectual disability, liver disease, and kidney problems.[2]
Last updated: 5/27/2011

How is galactosemia diagnosed?

Newborn screening programs in many states will test for galactosemia. The diagnosis of this condition is usually established by measurement of erythrocyte galactose-1-phosphate uridyltransferase (GALT) enzyme activity, erythrocyte galactose-1-phosphate (gal-1-P) concentration, and genetic testing looking for mutations in the GALT gene. In classic galactosemia, GALT enzyme activity is less than 5% of control values and erythrocyte gal-1-P is higher than 10 mg/dL.[3]
Last updated: 5/27/2011

How might galactosemia be treated?

When treatment starts before a baby is 10 days old, there is a much better chance for normal growth, development and intelligence.[1] Affected individuals must avoid all milk, milk-containing products (including dry milk), and other foods that contain galactose for life. It is essential to read product labels and be an informed consumer. Infants can be fed with soy formula, meat-based formula or Nutramigen (a protein hydrolysate formula), or another lactose-free formula. Calcium supplements are also recommended.[2] 

Because the body also makes some galactose, symptoms cannot be completely avoided by removing all lactose and galactose from the diet.  Researchers are working on finding a treatment to lower the amount of galactose made by the body, but there is no effective method to do so at this time.[1]

The Screening, Technology, and Research in Genetics (STAR-G) Project is a US-based organization that provides information on newborn screening. They provide comprehensive information for treatment on galactosemia. To view this information, click here.

Last updated: 5/27/2011

References
  1. Genetic Fact Sheets for Parents: Galactosemia. STAR-G. http://www.newbornscreening.info/Parents/otherdisorders/Galactosemia.html. Accessed 5/27/2011.
  2. Galactosemia. Genetics Home Reference. January 2008; http://www.ghr.nlm.nih.gov/condition=galactosemia. Accessed 6/9/2011.
  3. Elsas LJ. Galactosemia. GeneReview. October 2010; http://www.ncbi.nlm.nih.gov/books/NBK1518/. Accessed 5/27/2011.
  4. Galactosemia. MedlinePlus. April 2009; http://www.nlm.nih.gov/medlineplus/ency/article/000366.htm. Accessed 5/27/2011.