Patient 1. A 2-years-old female infant was referred to the First Affiliated Hospital, Jinan University, due to elevated serum total bile acids (TBA) discovered for 21 months. At the age 3 months, she was admitted to Women and Children's Hospital of Quanzhou because of jaundice for 2 months. Laboratory test revealed that the serum levels of TBA, direct bilirubin (DBIL), aspartate transaminase (AST) and alanine transaminase (ALT) were all elevated (Table ), and she was thus diagnosed to have cholestatic liver disease. After being treated with intravenous reduced glutathione and ademetionine-1,4-butanedisulfonate for 9 days, which were commonly used in cholestatic patients with elevated alanine transaminase levels, her jaundice was alleviated, but the liver function indices remained abnormal (Table ). Then oral ursodesoxycholic acid was given and she was discharged at the age 3.3 months. During the subsequent follow-up over 20 months, she showed normal anthropometric and neurobehavioral development without abnormal appearance, and her cholestasis resolved completely since the age 7 months. However, persistently raised TBA levels were observed on repeated biochemical analyses (Table ). So she was referred to our hospital for further investigation and management when aged 2 years.\nThe patient was the elder sister of two monochorionic diamniotic twins who was delivered by cesarean section at the gestation age of 37 weeks and 2 days with the birth weight 2.25 kg and body length 45.0 cm. Her father is a hepatitis B virus (HBV) carrier who was clinically healthy but with slightly elevated serum TBA level on biochemistry analysis, and her mother was physically and biochemically healthy (Table ). There was no family history of any genetic disease.\nPhysical examination revealed a body weight of 12.0 kg, height 83.5 cm and head circumference 46.0 cm. No jaundice was observed in the skin and sclera. No stridor, crackles or crepitus was heard in the two lungs, and the heart sound was normal without any murmurs. There was no abdominal distention, and the liver and spleen were non-palpable. Physiological reflexes were normal and no pathological reflexes could be found on nervous system examination. On biochemical analysis, the TBA level reached 173.8 μmol/L (0–10 μmol/L) as other indices were normal (Table ).
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 [].