Classic galactosemia type I is a metabolic disorder. It causes a low level or lack of an enzyme called galactose-1-phosphate uridyltransferase. This enzyme changes galactose to glucose. Galactose is a simple sugar found in milk products. Glucose is the usable form of sugar in the human body.
Since there is not enough of the enzyme, galactose builds up in the blood. This build up can cause severe damage to the liver, kidneys, central nervous system, and other body systems. If undetected, galactosemia is fatal.
Type II is a less severe form of this disease due to low levels of galactose kinase. This type may be managed with a few dietary restrictions. It does not carry the risk of neurologic or liver damage.
Type III is a form with variable severity due to low levels of galactose epimerase. This type can cause cataracts, delayed growth and development, intellectual disability, liver disease, and kidney problems.
This sheet will focus on classic galactosemia.
Galactosemia is a genetic condition. It is caused by faulty genes that are inherited from both parents. At least one normal copy of these genes is needed to make the enzyme correctly.
An infant with classic galactosemia usually appears normal at birth. Symptoms usually occur within the first few days or weeks of life after the baby drinks breastmilk or a lactose-containing formula.
Early symptoms may include:
- Yellowing of the skin and whites of the eyes
- Poor weight gain
- Feeding difficulties
If left untreated, later symptoms and complications may include:
- Opaque lenses of the eyes known as cataracts
- Enlarged liver
- Enlarged spleen
- Intellectual disability
- Sepsis caused by a specific bacteria
- Scarring of the liver— cirrhosis
- Liver failure
- Kidney problems
- Swelling of the extremities or abdomen
If dietary restrictions are started right away, it may be possible to prevent acute toxicity. However, long-term complications may still occur. These may include:
- Poor growth
- Learning disabilities
- Speech and language problems
- Fine and gross motor skill delays
- Ovarian failure
- Cataracts—usually regress with dietary treatment, leaving no remaining visual impairment
- Decreased bone mineral density—usually from lack of dairy products
Most infants in the US are screened for galactosemia at birth. A small sample of blood is taken with a heel prick. If this screen is positive further testing will be done to confirm the diagnosis. This may include genetic testing.
It is also possible to diagnose galactosemia during pregnancy with an amniocentesis . This test is only done if the baby is at high risk for an illness or condition.
|Copyright © Nucleus Medical Media, Inc.|
Your doctor may also suspect galactosemia after a urine test. The diagnosis can be confirmed with a blood test, including enzyme levels, or with a biopsy of the liver or other tissues.
Galactosemia cannot be cured. Steps can be taken to prevent or minimize symptoms and complications.
Infants can be fed with a soy formula. For further guidance a dietitian with a specialty in galactosemia can help create a dietary plan.
Avoid all products that contain or produce galactose. This includes:
- Standard formula
- Breast milk
Dairy products including
- Cow milk
- Lactose—milk sugar
- Dry milk solids
Galactose can also be found in some non-milk products, such as:
- Fermented soy products
- Organ meats
- Tomato sauces
Lactose or galactose may be used as an additive in some food products. Therefore, always read food labels carefully in order to avoid these foods.
Certain medications have galactose or lactose fillers. Check with the pharmacist before using medications.
Avoid supplements unless prescribed by a doctor. Fillers and inactive ingredients, like galactose are not required to be listed in supplements.
There is no known way to prevent galactosemia. You may consider genetic counseling if you have galactosemia or have a family history of the disorder. The counselor can help you determine the risk of passing the condition to your children.
American Liver Foundation. http://www.liverfoundation.org
Galactosemia Foundation http://www.galactosemia.org
Save Babies Through Screening Foundation http://www.savebabies.org
Sick Kids—The Hospital for Sick Children http://www.sickkids.ca
Berry GT. Classic cglactosemia and clinical variant galactosemia.GeneReviews website. Available at: http://www.ncbi.nlm.nih.gov/books/NBK1518.
Welling L, et al. International clinical guideline for the management of classical galactosemia: diagnosis, treatment, and follow-up. J Inherit Metab Dis. 2017; 40(2): 171-176. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5306419/.
Galactose screening test for galactosemia. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/topics/dmp~AN~T906909/Galactose-screening-test-for-galactosemia . Updated July 7, 2017. Accessed August 23, 2017.
The galactosemias. Galactosemia Foundation website. Available at: http://www.galactosemia.org/understanding-galactosemia. Accessed September 18, 2017.
- Reviewer: EBSCO Medical Review Board Michael Woods, MD, FAAP
- Review Date: 09/2018
- Update Date: 11/14/2017