Background: Dubin-Johnson syndrome (DJS) is a rare autosomal recessive genetic disease which is caused by mutations in the ABCC2 gene; it is characterized by chronic hyperbilirubinemia. Here, we report two pedigrees affected with DJS which were caused by three novel pathogenic ABCC2 mutations. Case summary: The two patients exhibited intermittent low-grade, predominantly conjugated hyperbilirubinemia and showed no other abnormalities. They were diagnosed clinically with DJS. Three novel pathogenic ABCC2 mutations-c.2980delA, c.1834C>T, and c.4465_4473delinsGGCCCACAG-were identified by whole-exome sequencing. These mutations could be responsible for DJS in the two pedigrees. The genetic test confirmed the diagnosis of DJS.

Conclusion: These results contributed to the genetic diagnosis of the two patients with DJS and expanded the variant database for the ABCC2 gene.