Patient 1. A 9-day-old female infant was admitted to the Neonatal Section of our Department of Pediatrics due to jaundice over 6 days. At her age of 3 days, jaundiced skin and sclera was noticed, which was then aggravated progressively. As the second product of a non-consanguineous couple, the infant was spontaneously delivered at the gestation age of 38 weeks and 2 days, with a birth weight of 2.85 kg and a body length 48 cm. The Apgar score was 9 points at 1 min after umbilical ligation, and 10 points at 5 min, while the amniotic fluid was clear. The patient had a 9-year-old brother, who was physically healthy with normal social performance. The parents were healthy, and there was not family history of any genetic disease.\nPhysical examination found a body temperature (T) 36.5°C, heart rate (HR) 140 beats/min , respiratory rate (RR) 45 breaths/min, and a body weight (WT) 2940 g. Jaundice was observed in the skin and sclera. The anterior fontanelle was flat and soft, and no malformation of the head, ears, nose, mouth, and eyes could be observed. No positive signs were found in the two lungs and the heart. Her liver and spleen were not enlarged. The extremities were warm, and the distal perfusion was excellent.\nAfter admission, the liver function test revealed indirect hyperbilirubinemia and markedly elevated serum TBA level. Her jaundice was alleviated soon in a response to phototherapy, but the TBA elevation persisted, even on the following-up in the clinic after she was discharged at the age of 19 days (Table ). When aged 25 days, the infant underwent SLC10A1 analysis to evaluate the possibility of NTCP deficiency. Sanger sequencing of the UGT1A1 gene was performed (), but no pathogenic variant was detected.
Patient 2. A 5-day-old male infant was admitted to our Neonatal Section because of jaundice for 3 days. Mild jaundice appeared at age 2 days. At the 5th day after birth, the total bilirubin increased to 310.1 μmol/L. Then the infant was referred to our clinic, where a laboratory test revealed elevated TBA as well as indirect hyperbilirubinemia (Table ), and thus the infant was admitted for further management. As the first child of a non-consanguineous couple, the patient was delivered vaginally at the gestational age of 37 weeks with the birth weight 3050 g. The parents were both healthy. Family history of any genetic disease was denied.\nOn physical examination, the body weight was 2910 g, with T 36.2°C, HR 130 beats/min, and RR 43 breaths/min. Jaundiced skin and sclera were observed. The lungs were clear on auscultation, and no abnormal heart sound or murmur was heard. There was no abdominal distention, and the liver and spleen were not palpable. Primitive reflexes were normal and no pathological reflexes could be found on nervous system examination.\nThe patient underwent phototherapy for 3 days. As a result, his jaundice subsided, and he was discharged at age 9 days. No special treatment was given thereafter, and the jaundice did not reappear. However, his serum TBA levels kept high in the following 1 month, and hence SLC10A1 analysis was performed at age 33 days to evaluate the possibility of NTCP deficiency. On Sanger sequencing of the UGT1A1 gene, no pathogenic variant was detected but three benign SNPs in the 3ʹ UTR, i.e. rs10929303, rs1042640 and rs8330 [].