Abstract: Objective To explore the clinical features and characteristics of genetic variation in congenital bile acid synthesis disorder type 2. Method The clinical data of congenital bile acid synthesis disorder type 2 in 8 children was retrospectively analyzed. Results Eight children ( 6 boys and 2 girls) had clinic visit for jaundice between 6 and 12 weeks after birth, and the median diagnosis age was 4 . 7 months. Six children had pale yellow stools, and all had cholestatic hepatitis with normal bile acid. There was normalγ-GT in 6 cases, coagulation disorder in 3 cases and amino acid changes in 5 cases. Color Doppler ultrasonography showed poor or no filling of gallbladder. AKR 1 D 1 gene mutation was found in all 8 cases. Four cases were AKR1D 1 homozygous variants, 3 cases were compound heterozygous variants, and one case was single-heterozygous variants. In combination with urine steroid analysis, the diagnosis was confirmed. Conclusions Cholestasis can be found in children with congenital bile acid synthesis disorder type 2 in early infancy. There is no obvious abnormality in γ - GT and bile acid, and coagulation dysfunction can be found in some cases. Gene and urine steroid detection can confirm the diagnosis.

Key words: bile acid synthesis disorders; gene; jaundice