Hereditary galactosemia is among the most common carbohydrate metabolism disorders and can be life threatening illness during the newborn period. Galactosemia is an inherited defect of galactose metabolism caused by an enzyme deficiency. It is an autosomal recessive defect and occurs at the average worldwide incidence of aprox. 1 :50000 but varies geographically. Cardinal features are hepatomegaly, cataracts and mental retardation.

Surviving babies who remain untreated may have mental retardation and other damage to the brain and nervous system. Classic galactosemia cannot be cured, but it can be effectively treated by eliminating lactose and galactose from the diet like milk and all dairy products, if detected in early stage of life and disease course.