What is a galactosemia test?

A galactosemia test is a blood test given to newborns to check for a rare genetic disorder called galactosemia. This disorder prevents the body from breaking down a simple sugar called galactose. Galactose is found in many foods and all dairy products. This includes breast milk and milk-based baby formulas.

Normally, certain enzymes break down galactose. Galactosemia happens when a genetic change affects the function of these enzymes. There are three types of galactosemia. The type depends on which enzyme is affected:

• GALT (galactose-1 phosphate uridyl transferase) deficiency. This is also known as classic galactosemia. It is the most common and severe form of the disorder.
• GALK (galactose kinase) deficiency
• GALE (galactose epimerase) deficiency

If a baby with a GALT, GALK, or GALE deficiency eats food with galactose, high levels of sugar build up in the blood. This can lead to serious health problems. These include liver disease, kidney failure, brain damage, and even death. But with early diagnosis and treatment, children with galactosemia can live healthy lives.

Other names: galactosemia newborn screening test, GALT test