galactosemia ga·lac·to·se·mia (gə-lāk'tə-sē'mē-ə)
An inherited metabolic disorder characterized by the deficiency of an enzyme necessary for galactose metabolism and chracterized by elevated levels of galactose in the blood and, if untreated, mental retardation and eye and liver abnormalities.
a hereditary defect in the metabolism of the sugar galactose, which is a constituent of lactose, the main carbohydrate of milk. Infants with this condition appear normal at birth, but, after a few days of milk feeding, they begin to vomit, become lethargic, fail to gain weight, and show an enlargement of the liver. Untreated infants who survive are usually malnourished and stunted in growth; cataracts in the eyes and mental retardation may also occur. When their urine is tested for sugars, galactose invariably is present. In all affected infants, the symptoms of galactosemia regress after milk and milk products are eliminated from their diet.
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