Galaktosemia

Galactosemia is a rare inherited metabolic disorder in which the body cannot properly metabolize galactose, a sugar in milk and other dairy products. It results from defects in the Leloir pathway enzymes that convert galactose to glucose. The most common and severe form, classic galactosemia, is caused by galactose-1-phosphate uridylyltransferase (GALT) deficiency. Other forms include galactokinase deficiency (GALK1) and UDP-galactose 4'-epimerase deficiency (GALE). A milder GALT-related Duarte variant is also described. It is inherited in an autosomal recessive pattern.

Classic galactosemia leads to accumulation of galactose-1-phosphate and related metabolites, causing liver disease, jaundice, vomiting, poor feeding, and an increased risk of sepsis in the newborn. If untreated, cataracts, growth retardation, liver failure, and neurodevelopmental impairment may occur. In females, premature ovarian insufficiency can develop later.

Diagnosis is often made by newborn screening. Confirmatory tests include measurement of GALT activity in blood and genetic testing of GALT, GALK1, or GALE genes.

Management requires lifelong restriction of dietary galactose, achieved by avoiding lactose-containing foods and using galactose-free formulas for infants. Regular medical follow-up monitors growth, nutrition, and potential complications. With early detection and strict diet, prognosis improves, although some individuals experience neurodevelopmental or reproductive sequelae despite treatment.