Galactosemia is an autosomal recessive disorder that results from the defective activity of galactose-1-phosphate uridyl transferase (GALT) enzyme. Newborns are typically asymptomatic, but may present with hyperbilirubinemia or E. coli sepsis. If an infant is not screened and/or left untreated, symptoms begin to appear early in infancy, and can include poor feeding, failure to thrive, liver dysfunction, and mental retardation
Incidence: ~1/30,000; affects all ethnic groups
Diagnosis: Quantification of erythrocyte galactose-1-phosphate (Gal-1-P) and GALT (usually ordered through a metabolic center). Classical galactosemia shows <1% GALT activity and markedly increased Gal-1-P.
Enzyme variants may be distinguished by GALT electrophoresis or mutation analysis.
Treatment: Evaluate the baby immediately and switch to soy-based formula. Refer to a metabolic center.
False Positives: Results can be impacted by transfusions, heat, and other environmental factors. Partial GALT activities can be due to milder variants