Mixed Dubin-Gilbert Syndrome: A Compound Heterozygous Phenotype of Two Novel Variants in ABCC2 Gene

Concurrence of novel mutations causing Gilbert's and Dubin-Johnson syndrome with poor clinical outcomes in a Han Chinese family

Dual-hereditary jaundice (Dubin-Johnson syndrome (DJS) and Gilbert's syndrome (GS)) is a rare clinical entity resulting from defects of the ATP binding cassette subfamily C member 2 (ABCC2) and UDP glucuronosyltransferase family 1 member A1 (UGT1A1) genes with autosomal recessive inheritance. In this study, we aimed to investigate the mutation profiles and characterize the phenotypes in a Han Chinese family with DJS and GS. Genetic screening for variants in the ABCC2 and UGT1A1, immunohistochemistry for expression of ABCC2, and histopathological examination were carried out. The proband and his brother had unconjugated and conjugated hyperbilirubinemia after birth. The proband's sister had only conjugated hyperbilirubinemia after birth. The proband developed into pleural effusions and ascites, pericardial thickening, intrahepatic and extrahepatic biliary duct dilatation, and enlarged gallbladder at age 50. Hepatocellular carcinoma occurred in the proband's brother at age 46. Seven compound defects of the ABCC2 gene [c.2414delG, p.(Ile1489Gly), p.(Thr1490Pro), and p.(Ile1491Gln)] and the UGT1A1 gene (c.-3279T>G, p.(Gly71Arg), and p.(Pro451Leu)) were identified in family members. Accumulation of pigment in hepatocytes characteristic of that in DJS was present in the proband and his brother. Expression of ABCC2 protein was markedly diminished in the patient's liver. Our results show a different genetic profile of DJS and GS in a Han Chinese family, indicating a more complex pattern of dual-hereditary jaundice among different populations. The present study illuminates the underpinnings of DJS and GS and extends the mutation profiles and phenotypes of these two syndromes in dual-hereditary jaundice.

Primary myelofibrosis with thrombophilia as first symptom combined with thalassemia and Gilbert syndrome: A case report

BACKGROUND

A 46-year-old Han man first had sigmoid sinus and transverse sinus venous thrombosis at the age of 42. At the age of 44, he once again developed thrombosis. Genetic testing showed heterozygous SERPINC1 mutation, bone marrow biopsy showed fibrosis grade 1 (MF-1), and JAK2 V617F mutation was positive, accompanied by UGT1A1 mutation and β-thalassemia gene mutation.

CASE SUMMARY

A 46-year-old Han man was first found to have sigmoid sinus and transverse sinus venous thrombosis at the age of 42 but had no individual or family thrombosis history, and he had been regularly taking warfarin anticoagulant therapy for a long period of time. At the age of 44, venous thrombosis reappeared in parts of the intrahepatic vein, main portal vein, splenic vein, and superior mesenteric vein, and his spleen was obviously enlarged. He had a history of jaundice for many years, and genetic testing revealed that he carried a heterozygous SERPINC1 mutation. Bone marrow biopsy showed multifocal fibrous tissue hyperplasia among trabeculae and focal fibrosis. He was positive for the JAK2 V617F mutation. At the same time, UGT1A1 and β-thalassemia gene mutations existed, and a SERPINC1 mutation and UGT1A1 mutation were both found in his parents.

CONCLUSION

The patient in this case had thrombophilia as the primary symptom, JAK2V617-positive myeloproliferative neoplasm (MPN) was the main potential cause, and hereditary AT-III deficiency may have been one of multiple secondary causes. It remains to be determined whether UGT1A1 and β-thalassemia gene mutations are related to thrombophilia. However, the clinical features of MPN in this patient were hidden, and the relevant clinical features of coexisting thalassemia and hereditary Gilbert syndrome, reported here for the first time domestically and abroad, were complicating factors, causing great difficulties for a clear diagnosis. Thus, when thrombophilia has been determined, it is necessary to screen the relevant latent problems overall. When the clinical features cannot be perfectly explained by one etiology, a relevant comprehensive examination should also be initiated from the perspective of multiple etiologies.