This study determined a TcB cut-off value of 4.5 mg/dL at the age of 24 hours for Group I (1000–1500 grams) and 5.8 mg/dL for Group II (1501–2000 grams) as predictive of hyperbilirubinemia at 48 hours. The gene discussed is PKM; the disease is Hyperbilirubinemia.