Abstract: Objective　To analyze the clinical manifestations and liver pathology of child with Alagille syndrome (ALGS) caused by 20p12 deletion. Method　Clinical data of one child with ALGS was retrospectively analyzed. Result　A male patient was 1 month old at onset with cholestasis as the first manifestation, accompanied by special face, butterfly vertebra, kidney and heart disease. Pathological examination of liver biopsy showed liver cholestasis, moderate hepatic cell damage (G2S3) and no sign of bile duct reduction. The blood samples of this child and his parents were collected. The next generation gene sequencing detected a de novo 1.36 MB heterozygous deletion in 20p12.2 (9,288,462-10,654,178) which contained the JAG1 gene. After the diagnosis, he was given supportive treatment. After half a year of follow-up, the growth and development were normal. His jaundice was still prolonged. The long-term prognosis needs further follow-up. Conclusion　ALGS is an autosomal dominant disease with diverse clinical manifestations. Genetic test and liver biopsy were helpful for diagnosis.

Key words: Alagille syndrome;　20p12.2 deletion;　JAG1 gene;　clinical manifestations;　liver pathology