Crigler-Najjar syndrome(CNS)is an autosomal recessive genetic disorder caused by mutations in the UGT1A1 gene.This author retrospectively analyzes the clinical data of one patient presenting with postnatal hyperbilirubinemia,who was genetically diagnosed with CNS.Her clinical course,genetic characteristics,diagnostic and therapeutic approaches are discussed to enhance clinicians'understanding of this condition.The patient exhibited recurrent jaundice due to elevated unconjugated bilirubin(UCB)levels since birth.During this period,the gallstones were identified and surgically removed,yet her bilirubin levels did not improve.In March 2024,the patient presented to our hospital and underwent genetic testing via a third-party facility.The results revealed two risk variants in the UGT1A1 gene.After one week of oral phenobarbital administration,her UCB levels decreased by approximately 47%,confirming a diagnosis of CNS type Ⅱ.The patient is currently under active follow-up with regular monitoring of bilirubin levels.For the infants and children presenting with persistent,fluctuating,non-hemolytic,and non-hepatitic hyperbilirubinemia since birth,early genetic testing should be prioritized to establish the definitive diagnosis.