Galactosemia is a genetic condition that renders the body incapable of digesting galactose, a sugar that makes up half of lactose, a sugar in dairy products. When the body cannot digest galactose, the sugar and its byproducts build up in the blood and tissues. Without prompt diagnosis and treatment, galactosemia can have serious complications including organ damage.


1. Classic Galactosemia (Galactosemia Type I)

Classic galactosemia is the most common and severe type of this recessive genetic disorder. Individuals who have classic galactosemia have a deficiency in the galactose-1-phosphate uridyl transferase (GALT) enzyme necessary for breaking down galactolose. Both parents must pass on a defective copy of the gene for their child to develop galactosemia. Two parents who carry the defective gene have a 25% chance of having a child with galactosemia.

galactosemia type I damircudic / Getty Images

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