Abstract: Objective To explore the clinical and genetic characteristics of progressive familial intrahepatic cholestasis (PFIC) caused by tight junction protein 2 (TJP 2 ) gene mutation. Method The clinical data of PFIC caused by TJP 2 gene mutation in 3 children were summarized and the relevant literature was reviewed. Results In all 3 children ( 1 girl and 2 boys), the onset was in infancy and jaundice was the main clinical manifestation with or without pruritus. The serum total bilirubin increased, mainly the direct bilirubin. Alanine aminotransferase, aspartate aminotransferase and total bile acid were elevated, and γ-glutamyl transpeptidase (GGT) was normal or slightly low. The changes of above indexes indicated low GGT cholestasis. The second generation gene sequencing showed that there were TJP2 complex heterozygous variants in all the 3 children, and all of them were diagnosed with PFIC 4 caused by TJP2 mutation. Literature review shows that TJP2 gene mutations can cause childhood diseases such as PFIC, hypercholanemia, progressive non-syndromic deafness, and myopia. Conclusion Three cases of PFIC 4 caused by composite heterozygous variation of TJP2 gene were diagnosed by gene detection.

Key words: intrahepatic cholestasis; TJP2 gene; gene detection