Snapshot A two-week-old infant is brought to the emergency department because of diarrhea, poor feeding, abdominal distention, and vomiting for the past 3 days. Physical exam reveals a temperature of 39 deg Celsius, cataracts, hepatomegaly, and jaundice. The mother says the only change has been that she recently began giving him milk products. Introduction Autosomal recessive errors of galactose metabolism Absence in galactose-1-phosphate uridyltransferase leads to genetic defects in the stepwise conversion of galactose to glucose accumulation of galactose 1-phosphate in liver, kidney, and brain incidence is 1/62,000 births carrier frequency is 1/125 Presentation An infant with classic galactosemia appears normal at birth upon being fed milk, will develop jaundice vomiting lethargy irritability convulsions Continued feeding of milk products to the infant leads to cataract formation hepatosplenomegaly mental retardation Evaluation Widespread screening in newborns often leads to early diagnosis. Screen for decreased RBC concentrations of galactose 1-phosphate uridyltransferase increased concentrations of galactose 1-phosphate (in serum and urine) Differential hereditary fructose intolerance presents with vomiting, lethargy, and seizures when fructose is consumed Treatment Treatment involves eliminating all sources of galactose in the diet most notably lactose which is present in all dairy products sweetener in many foods. Although a lactose-free diet often prevents acute toxicity, long-term complications are common including poor growth speech and neurologic abnormalities mental deficiency Prognosis, Prevention, and Complications If diagnosis is made early and milk products are strictly avoided the prognosis is for a normal life Without optimal treatment, the child remains physically stunted and mentally retarded many also have cataracts and rickets most female patients have ovarian failure