Novel Large-scale Deletion (whole Exon 7) in the ABCC2 Gene in a Patient with the Dubin-Johnson Syndrome

Summary:The Dubin-Johnson syndrome (DJS) is an inherited liver disorder characterized by conjugated hyperbilirubinemia and caused by ABCC2 gene mutations resulting in deficiency of multidrug resistance associated-protein 2 (MRP2) function. A 76-year-old woman with serious jaundice was referred to our hospital. She was clinically diagnosed with DJS with hepatic congestion, due to constrictive pericarditis. We analyzed all exons and exon-intron junctions of the ABCC2 gene by DNA sequencing and identified a new large-scale deletion, 1008 bp, including the whole exon 7, as homozygosity. Some mutations in the ABCC2 gene associated with splicing errors have been reported in intronic regions; however, this is a new type of large-scale deletion detectable in the genomic DNA sequence. Severe hyperbilirubinemia is rare in patients with constrictive pericarditis and this case suggests that MRP2 may play a crucial role in compensating for the serum bilirubin in congestive hepatopathy.