OBJECTIVE: To explore the clinical manifestations and genetic etiology of a child with Progressive familial intrahepatic cholestasis (PFIC2). METHODS: From April 2024 to June 2024, a child with jaundice, hepatomegaly and abnormal liver function who was repeatedly admitted to the First Department of Pediatrics of Qinzhou Maternal and Child Health Care Hospital was selected as the study subject. Clinical data of the child were collected. Peripheral blood samples were collected from the child and her parents. Genomic DNA was extracted for trio-whole exome sequencing, the candidate variant was verified by Sanger sequencing and bioinformatic analysis using REVEL, BLAST/BLAT, Swiss-Model and Swiss-Pdb Viewer software. This study was approved by the Medical Ethics Committee of the Qinzhou Maternal and Child Health Care Hospital (Ethics No.: L20240116). RESULTS: The child was a 1.5-month-old female. Her main clinical manifestations included jaundice, hepatomegaly, brownish urine and earth-like stool. Laboratory examination showed increased levels of bilirubin, mainly direct bilirubin, increased aminotransferase, especially glutamic oxalacetic aminotransferase, accompanied by increased bile acid. Genetic testing revealed that the she has harbored a homozygous c.3410T>G (p.V1137G) variant of the ABCB11 gene, for which both of her parents were heterozygous carriers. The variant was unreported previously, and was predicted to be pathogenic based on REVEL. Prediction with BLAST/BLAT software showed that the amino acids were highly conserved among different species. Swiss-Pdb Viewer software predicted that the variant has resulted in changes in hydrogen bonds between amino acids. According to the guidelines from the American Collage for Medical Genetics and Genomics (ACMG), the variant was determined to be likely pathogenic (PM1+PM2_Supporting+PM3_Supporting+PP3_Moderate). CONCLUSION The homozygous variant of the ABCB11 gene may be the genetic cause of this child. Genetic testing is helpful for confirming the diagnosis and enrich the mutational spectrum of the ABCB11 gene.
Humans ; Cholestasis, Intrahepatic/genetics* ; Female ; Infant ; ATP Binding Cassette Transporter, Subfamily B, Member 11/genetics* ; Homozygote ; Mutation

OBJECTIVE: To explore the genetic etiology for a pedigree affected with progressive familial intrahepatic cholestasis (PFIC). METHODS: Target sequence capture and next generation sequencing (NGS) were applied for the proband. PCR and Sanger sequencing were used to verify the suspected mutation in his sister with similar symptoms and his parents. RESULTS: The proband and his sister manifested after birth with symptoms including jaundice, pruritus and developmental retardation. NGS has identified compound heterozygous mutations of ABCB11 gene, which encodes bile salt export pump protein (BSEP), namely c.2494C>T (p.Arg832Cys) and c.3223C>T (p.Gln1075*), in the proband, which were inherited from his father and mother respectively. His sister carried the same compound mutations. CONCLUSION Based on the phenotype and genetic testing, the patients were diagnosed as PFIC2 caused by mutation of the ABCB11 gene. The c.3223C>T is a novel nonsense mutation which may cause premature termination of translation. Above results have enriched the spectrum of ABCB11 mutations and provided new evidence for the molecular basis of PFIC, which also facilitated genetic counseling for this pedigree.
ATP Binding Cassette Transporter, Subfamily B, Member 11 ; genetics ; ATP-Binding Cassette Transporters ; Cholestasis, Intrahepatic ; genetics ; Female ; Genetic Testing ; Humans ; Male ; Mutation ; Pedigree ; Phenotype