A to Z: Galactosemia

May also be called: Galactose-1-Phosphate Uridyltransferase Deficiency; Galactokinase Deficiency; Galactose-6-Phosphatase Emirase Deficiency; GALT Deficiency; Galactose Epimerase Deficiency; Classic Galactosemia; Galactosemia Type II; Galactosemia Type III

Galactosemia (guh-lak-tuh-SEE-mee-uh) is an inherited disorder in which the body can't break down a type of sugar called galactose.

More to Know

Galactose is one of the two sugars found in lactose, or milk sugar. It's also in some fruits and vegetables. Galactosemia is caused by mutations (changes) in genes that help make enzymes the body needs to change galactose into glucose.

The parents of a child with galactosemia are carriers of the mutation. This means they have the gene in their bodies and can pass it on, but won't show any signs of the condition themselves.

Babies with galactosemia don't have the enzyme that changes galactose into glucose, a sugar the body uses. If babies drink milk or other products with lactose or galactose, galactose can build up in the body and damage cells and organs. This can lead to blindness, impaired mental development, growth problems, and in some cases even death.

Galactosemia usually appears within the first few days or weeks after a baby's birth. Newborns with galactosemia often have symptoms like vomiting, poor feeding, loss of appetite, yellowed skin and whites of the eyes (jaundice), and failure to thrive (they don't grow and gain weight properly). They also may have enlarged livers (hepatomegaly).

To treat galactosemia, milk (including breast milk), other dairy products, and other sources of lactose and galactose must be removed from the baby's diet. This may help control symptoms. Even with the proper dietary changes, though, galactosemia often causes serious long-term problems.

Keep in Mind

If not treated, galactosemia quickly can become life-threatening. Fortunately, newborns can be screened for the condition. Treatment usually starts before a child becomes seriously ill and has permanent organ damage. Children who are diagnosed early and eat a lactose-free and galactose-free diet usually reach adulthood.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.