Galactosemia is a disorder that affects how the body processes a simple sugar called galactose.  The signs and symptoms of galactosemia result from an inability to use galactose to produce energy. Researchers have identified several types of galactosemia. These conditions are each caused by mutations in a particular gene and affect different enzymes involved in breaking down galactose. There are 3 types of galactosemia. Type I, type II, and type III galactosemia are also called?