galactosemia /gəlak′tōsē″mē·ə/ [Gk, gala + glykys, sweet, haima, blood] , a group of inherited autosomal-recessive disorders of galactose metabolism. It is characterized by a deficiency of an enzyme involved in galactose metabolism, galactose-1-phosphate uridyl transferase. Shortly after birth an intolerance to milk occurs; it is evidenced by anorexia, nausea, vomiting, and diarrhea and causes failure to thrive. Hepatosplenomegaly, cataracts, and cognitive impairment develop. Greater than normal amounts of galactose are present in the blood, the galactose tolerance test result indicates an abnormality, and the red cells show deficient galactose enzyme activity. Because the elimination of galactose from the diet results in the rapid decrease of all symptoms except cognitive impairment, early diagnosis and prompt therapy are essential. Pregnant women known to be carriers should exclude lactose and galactose from their diet. Compare glycogen storage disease. See also galactose, inborn error of metabolism.
