Galactosemia is a rare metabolic disorder passed through genes from parents to their children. Galactosemia occurs in approximately 1 in 60,000 births in the United States (U.S.). Children with galactosemia are unable to breakdown (metabolize) galactose, a simple sugar. Galactose combines with glucose (a source of energy for the body) to make lactose, a complex sugar commonly found in human milk, animal milks (cow, goat), and milk products.
Galactosemia should not be confused with lactose-intolerance or cow’s milk allergy. People who are lactose intolerant are unable to metabolize lactose, but can usually breakdown galactose. Lactose intolerance is rare in infants and more common in older children and adults. Symptoms of lactose intolerance include bloating, cramping, and diarrhea. It is easily treated by avoiding foods containing lactose, particularly milk and milk products. Cow’s milk allergy is among the more common food allergies. Symptoms include fussiness, gassiness, and diarrhea. Like lactose intolerance, treatment calls for avoiding foods with cow’s milk. Children usually outgrow cow’s milk allergy by 3–5 years of age. Unlike lactose intolerance or cow’s milk allergy, undiagnosed galactosemia can be a life-threatening condition.
Symptoms of galactosemia (vomiting, poor weight gain, irritability, refusal to breast or bottle-feed) appear within days of drinking human milk or cow’s milk formula. If galactosemia is identified early, babies can be put on a galactose-free diet and there is little risk for permanent damage. If diagnosis is delayed for weeks or months, irreversible damage can occur.
Types of galactosemia
Galactose is converted into glucose by three enzymes. When one of the enzymes is missing, galactose builds up in the blood. High levels of galactose can damage a baby’s brain, liver, and kidneys. There are three types of galactosemia depending upon which enzyme is missing:
Type 1—Galactose-1 phosphate uridyl transferase deficiency (classic galactosemia)
Type 2—Deficiency of galactose kinase
Type 3—Deficiency of galactose-6-phosphate epimerase
The classic form of galactosemia (type 1) is the most common and the most severe. Babies with classic galactosemia are unable to metabolize even small amounts of galactose; whereas babies with type 2 or 3, also called the Duarte form of galactosemai, are usually able to metabolize some galactose. As a result, babies with type 2 or 3 may have fewer, albeit some, dietary restrictions depending upon how much galactose they are able to metabolize. Because it is difficult to know how much galactose a child can eat without there being adverse effects, many parents of children with type 1 and 2 galactosemia choose to avoid galactose altogether. However, others choose to partially breastfeed and monitor galactose levels.
State laws require that all U.S. babies be tested for galactosemia soon after birth. A small sample of blood is taken from the baby’s heel and sent to a state lab for testing. In order for the test to be accurate, babies must be drinking breast milk or formula for at least 24 hours. If one parent has galactosemia, both parents can have genetic testing done to determine the risk of having a child with the disorder.
Managing galactosemia: diet
Galactosemia is a lifelong condition that children will not outgrow. However, galactosemia can be easily managed by following a galactose-free diet. Galactose is derived from the complex sugar, lactose, so any food containing lactose (milk and milk products) should be avoided as well. The majority of fruits, vegetables, grains, breads, fats, and sugars are safe to eat as long as they contain little or no galactose.
Product labels on packaged foods list the ingredients found in each product. Check labels carefully each time you shop, since ingredients can change without notice.
Ingredients you want to avoid include:
Common ingredients that do not contain lactose include:
Foods that contain 5–10mg of galactose in each 100 gm serving:
(This list is provided for those individuals with type 2 or 3 galactosemia who may be able to eat small amounts of galactose.)
Foods to avoid:
For more information on the amount of lactose in foods visit the Parents of Children with Galactosemia website.
Managing galactosemia: lifestyle
Researchers have begun to examine the long-term consequences of galactosemia. Research suggests that despite early diagnosis, there may still be developmental delays. IQ values may be normal, but children with galactosemia have been found to exhibit a range of learning problems including speech and language deficits and problems with visual perception and social adjustment. This is not true of all children with galactosemia, but the fact that it occurs in some children highlights the importance of early diagnosis and strict dietary control.
What can parents do?
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