A pedigree analysis of Rotor hyperbilirubinemia combined with hepatitis B virus infection in a SLCO1B1 and SLCO1B3 gene mutations patient

Abstract

BackgroundRotor syndrome (RS, OMIM#237450) is an extremely rare autosomal digenic recessive disorder characterized by mild non-hemolytic hereditary conjugated hyperbilirubinemia, caused by biallelic variation of SLCO1B1 and SLCO1B3 genes that resulted in OATP1B1/B3 dysfunction in the sinusoidal membrane leading to impaired bilirubin reuptake ability of hepatocytes. MethodsOne RS pedigree was recruited and clinical features were documented. Whole genome second-generation sequencing was used to screen candidate genes and mutations, Sanger sequencing confirmed predicted mutations. ResultsThis study detected a homozygous nonsense variant c.1738C > T (p.R580*) in the coding region of the SLCO1B1 (NM006446) gene in a family with RS and hepatitis B virus infection by Variants analysis and Sanger sequencing, and confirmed by Copy Number Variation (CNV) analysis and Long Range PCR that there was a homozygous insertion of intron 5 of the SLCO1B3 gene into intron 5 of long-interspersed element 1 (LINE1). A few cases of such haplotypes have been reported in East Asian populations. A hepatitis B virus infection with fatty liver disease was indicated by pathology, which revealed mild-moderate lobular inflammation, moderate lobular inflammation, moderate hepatocellular steatosis, and fibrosis stage 1–2 (NAS score: 4 points/S1-2) alterations. Heterozygotes carrying p.R580* and LINE1 insertions were also detected in family members (I1, I2, III2, III3), but they did not develop conjugated hyperbilirubinemia. ConclusionThe mutations may be the molecular genetic foundation for the presence of SLCO1B1 c.1738C > T(p.R580*) and SLCO1B3 (LINE1) in this RS pedigree.