A condition in which the body can't use a simple sugar to make energy.

A baby born with galactosemia can't use the sugar galactose to make energy. Galactose is part of lactose, which is found in breast milk, dairy products and many baby formulas. A gene change passed through families causes the condition.

Babies may fail to thrive, have liver problems and have trouble eating. They might get infections easily, and the infections can lead to life-threatening sepsis. Even with treatment, teens and adults with the condition might have cataracts, growth delay, early failure of the ovaries and trouble with thinking, speech and language.

Treatment includes a diet without breast milk or formula that has dairy products. Soy-based formulas are given instead.