What are the signs and symptoms of galactosemia?
In newborns, signs of classic galactosemia begin to appear after a few days of feeding. Symptoms can be mild or severe and may include:
These symptoms require immediate medical attention. After a healthcare provider diagnoses galactosemia and you remove galactose from your baby’s diet, these symptoms should improve.
What causes galactosemia?
Galactosemia happens because of a gene mutation. You have to inherit it from both parents to get it. Each parent provides one copy of the mutated gene. But unless both copies of their galactosemia genes are mutated, the parents typically won’t have symptoms of the condition themselves, so symptoms in their baby can come as a surprise.
The mutated gene fails to produce the enzymes necessary to break down galactose for energy. This causes chemical products of galactose to accumulate in your body. There are three different genes involved that may be mutated. Each corresponds to a different type of galactosemia.
What are the different types of galactosemia?
Type I (Classic)
The classic version of galactosemia, which is also called type I, is the most common and also the most severe. Type I is caused by a mutation in the GALT gene. This gene is responsible for making the enzymes that break down galactose into glucose and other molecules that your body can use for energy. The type I gene mutation essentially eliminates this enzyme activity, leaving your body unable to process galactose at all. This causes galactose to accumulate quickly in your body.
Type II (Galactokinase deficiency)
A mutation of the GALK1 gene causes the type II variant. This gene makes enzymes that play a supportive role in galactose metabolism. Type II causes fewer medical problems than the classic type. The primary risk from type II is that you may develop cataracts.
Type III (Galactose epimerase deficiency)
The GALE gene, which produces enzymes that also play a supportive role in galactose metabolism, causes type III galactosemia. Any shortage of these important enzymes will eventually lead to accumulation of galactose in your body. Type III can manifest with mild or severe symptoms. The more severe version can lead to many of the more serious complications of classic galactosemia, including cataracts, developmental delays, intellectual disabilities, liver disease and kidney problems.
Duarte galactosemia
Duarte galactosemia happens due to mutations in the GALT gene, the same gene that causes classic galactosemia. It’s simply a less severe mutation. It reduces but doesn’t eliminate the essential enzyme function responsible for metabolizing galactose. People with Duarte galactosemia may have some digestive difficulties from foods containing galactose, but they don’t have the same medical complications. They don’t necessarily have to avoid galactose in their diet.
How do you treat galactosemia?
The only known way to treat galactosemia is to eliminate galactose from your diet. Galactose is a component of lactose, so this usually means avoiding dairy products. Newborns can receive a soy-based or elemental formula. Children and adults may need to supplement their calcium and vitamin D intake to make up for the lack of dairy products in their diet. Supplementing with calcium and vitamin D helps to maintain bone density.
What treatment will my child require for long-term side effects of galactosemia?
Some children may require extra support with learning and development as they grow up. This might include:
- Speech therapy.
- Occupational therapy.
- Behavioral therapy.
- Targeted learning plans.
Teenagers may require hormone therapy in order to induce puberty and menstruation.
How is galactosemia diagnosed?
In the U.S. it is standard procedure to screen newborn babies for a list of disorders — including classic galactosemia — that can cause significant damage before symptoms appear. (This is sometimes called the PKU test, which refers to phenylketonuria, another condition this test can detect.) The screening is done by pricking your baby’s heel and drawing a little blood, usually about 24 hours after they are born. If your child has galactosemia, the blood test will show reduced GALT enzyme activity in their blood. Your healthcare team will follow up these results with genetic testing to identify the type of galactosemia your child has.
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