A nurse is caring for a 1-day-old newborn whose caregiver reports that their child refuses to breast or bottle feed. The nurse performs an assessment and notes the newborn is lethargic and refuses to feed. Which of the following disorders would the nurse suspect?

A. Phenylketonuria (PKU): PKU is an inborn error of metabolism that typically does not present immediately at birth. Newborns are usually asymptomatic until phenylalanine accumulates, causing developmental delays if untreated, so refusal to feed on day 1 is not characteristic. B. Galactosemia: Galactosemia is a metabolic disorder in which the newborn cannot properly metabolize galactose. Classic early signs include lethargy, vomiting, jaundice, and refusal to breast or bottle feed within the first days of life, making this the most likely diagnosis. C. Beta thalassemia minor: This condition is generally asymptomatic and does not present with lethargy or feeding refusal in the newborn period. It usually manifests later with mild anemia. D. Hepatoblastoma: Hepatoblastoma is a rare liver tumor that typically presents later in infancy with abdominal mass or hepatomegaly and does not cause lethargy or immediate feeding refusal in a 1-day-old newborn.