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Khabou B, Kallabi F, Abdelaziz RB, Maaloul I, Aloulou H, Chehida AB, Kammoun T, Barbu V, Boudawara TS, Fakhfakh F, Khemakhem B, Sahnoun OS. Molecular and computational characterization of ABCB11 and ABCG5 variants in Tunisian patients with neonatal/infantile low-GGT intrahepatic cholestasis: Genetic diagnosis and genotype-phenotype correlation assessment. Ann Hum Genet 2024; 88:194-211. [PMID: 38108658 DOI: 10.1111/ahg.12542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/19/2023]
Abstract
Many inherited conditions cause hepatocellular cholestasis in infancy, including progressive familial intrahepatic cholestasis (PFIC), a heterogeneous group of diseases with highly overlapping symptoms. In our study, six unrelated Tunisian infants with PFIC suspicion were the subject of a panel-target sequencing followed by an exhaustive bioinformatic and modeling investigations. Results revealed five disease-causative variants including known ones: (the p.Asp482Gly and p.Tyr354 * in the ABCB11 gene and the p.Arg446 * in the ABCC2 gene), a novel p.Ala98Cys variant in the ATP-binding cassette subfamily G member 5 (ABCG5) gene and a first homozygous description of the p.Gln312His in the ABCB11 gene. The p.Gln312His disrupts the interaction pattern of the bile salt export pump as well as the flexibility of the second intracellular loop domain harboring this residue. As for the p.Ala98Cys, it modulates both the interactions within the first nucleotide-binding domain of the bile transporter and its accessibility. Two additional potentially modifier variants in cholestasis-associated genes were retained based on their pathogenicity (p.Gly758Val in the ABCC2 gene) and functionality (p.Asp19His in the ABCG8 gene). Molecular findings allowed a PFIC2 diagnosis in five patients and an unexpected diagnosis of sisterolemia in one case. The absence of genotype/phenotype correlation suggests the implication of environmental and epigenetic factors as well as modifier variants involved directly or indirectly in the bile composition, which could explain the cholestasis phenotypic variability.
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Affiliation(s)
- Boudour Khabou
- Molecular and Functional Genetics Laboratory, Faculty of Sciences, University of Sfax, Sfax, Tunisia
| | - Fakhri Kallabi
- Molecular and Human Genetics Laboratory, Faculty of Medicine, University of Sfax, Sfax, Tunisia
| | - Rim Ben Abdelaziz
- Department of Pediatrics, Hospital La Rabta, Tunis, Tunisia
- Faculty of Medicine of Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Ines Maaloul
- Department of Pediatrics, University Hospital Hedi Chaker, Sfax, Tunisia
| | - Hajer Aloulou
- Department of Pediatrics, University Hospital Hedi Chaker, Sfax, Tunisia
| | | | - Thouraya Kammoun
- Department of Pediatrics, University Hospital Hedi Chaker, Sfax, Tunisia
| | - Veronique Barbu
- LCBGM, Medical Biology and Pathology Department, APHP, HUEP, St Antoine Hospital, Sorbonne University, Paris, France
| | | | - Faiza Fakhfakh
- Molecular and Functional Genetics Laboratory, Faculty of Sciences, University of Sfax, Sfax, Tunisia
| | - Bassem Khemakhem
- Plant Biotechnology Laboratory, Faculty of Sciences, Sfax University, Sfax, Tunisia
| | - Olfa Siala Sahnoun
- Molecular and Functional Genetics Laboratory, Faculty of Sciences, University of Sfax, Sfax, Tunisia
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Zhang Y, Zuo W, Gao W. Clinical characteristics and follow-up of a newborn with Dubin-Johnson Syndrome: A clinical case report. Medicine (Baltimore) 2024; 103:e36991. [PMID: 38277553 PMCID: PMC10817024 DOI: 10.1097/md.0000000000036991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 12/26/2023] [Indexed: 01/28/2024] Open
Abstract
BACKGROUND Dubin-Johnson syndrome (DJS) is a rare autosomal recessive liver disorder, characterized by conjugated hyperbilirubinemia. This case report investigates the clinical characteristics and longitudinal outcomes of a neonate diagnosed with DJS. METHODS A newborn presented with elevated bilirubin levels and abnormal liver enzyme readings. Comprehensive genetic evaluation was conducted, which included peripheral blood sample collection from the infant and both parents after obtaining informed consent and high-throughput trio exome sequencing was performed. The genetic analysis revealed 2 significant mutations in the ABCC2 gene on chromosome 10: the insertion mutation c.4237(exon30)_c.4238(exon30)ins CT, inherited from the father, and the missense mutation c.517(exon5)G > A, inherited from the mother. Both mutations were classified as pathogenic according to the ACMG 2015 guidelines, indicating a compound heterozygous inheritance pattern. The patient's treatment regimen included phototherapy, which was initiated to address her jaundice upon admission. To support liver function and regulate gut activity, oral ursodeoxycholic acid (20 mg/kg/dose, twice a day) and probiotics were administered. Additionally, a postdischarge medication plan involving a low-dose regimen of phenobarbital (3.5 mg/kg/dose, twice a day) was implemented for 2 weeks. RESULTS During a 2-year follow-up after discharge, the infant's bilirubin levels significantly decreased, and liver enzymes, including GGT, progressively normalized. CONCLUSION This case report enhances the understanding of DJS in neonates by emphasizing the clinical ramifications of compound heterozygous mutations within the ABCC2 gene and documenting the evolution of the disease. The gradual normalization of liver function tests suggests potential compensatory mechanisms in response to the genetic abnormalities in neonates with DJS. The correlation between the patient's genetic profile of compound heterozygosity and her milder clinical phenotype warrants attention, suggesting that this specific genetic configuration may be associated with less severe manifestations of the disease. The necessity for long-term follow-up is highlighted, recognizing that intercurrent stress conditions could influence the hepatic profile and potentially exacerbate symptoms. Such sustained observation is crucial to further delineate the genomic and clinical landscape of DJS, offering opportunities to refine prognostic and therapeutic approaches.
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Affiliation(s)
- Yanmin Zhang
- Department of Neonatal Surgery, Anhui Provincial Children's Hospital (Anhui Hospital, Pediatric Hospital of Fudan University), Hefei, Anhui, China
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Kim JH, Kang MW, Kim S, Han JW, Jang JW, Choi JY, Yoon SK, Sung PS. Genotype-Phenotype Association in ABCC2 Exon 18 Missense Mutation Leading to Dubin-Johnson Syndrome: A Case Report. Int J Mol Sci 2022; 23:ijms232416168. [PMID: 36555809 PMCID: PMC9781201 DOI: 10.3390/ijms232416168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
We report a case of a patient with Dubin-Johnson syndrome confirmed by a genetic study. A 50-year-old woman who had symptoms of intermittent right upper quadrant abdominal pain was diagnosed with calculous cholecystitis at another institute and was presented to our hospital for a cholecystectomy. She had no history of liver disease, and her physical examination was normal. Abdominal computed tomography showed a gallbladder stone with chronic cholecystitis. During a laparoscopic cholecystectomy for cholecystitis, a smooth, black-colored liver was noted, and a liver biopsy was performed. The biopsy specimen showed coarse, dark brown granules in centrilobular hepatocytes via hematoxylin and eosin staining. We performed a genetic study using the blood samples of the patient. In the adenosine triphosphate-binding cassette subfamily C member 2 (ABCC2) mutation study, a missense mutation in exon 18 was noted. Based on the black-colored liver without nodularity, conjugated hyperbilirubinemia, the liver biopsy results of the coarse pigment in centrilobular hepatocytes, and the ABCC2 mutation, Dubin-Johnson syndrome was diagnosed. The patient was managed with conservative care using hepatotonics. One month after follow-up, total bilirubin and direct bilirubin remained in a similar range. Another follow-up was planned a month later, and the patient maintained her use of hepatotonics.
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Affiliation(s)
- Ji-Hoon Kim
- The Catholic University Liver Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Min-Woo Kang
- The Catholic University Liver Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Sangmi Kim
- The Catholic University Liver Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Ji Won Han
- The Catholic University Liver Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Jeong Won Jang
- The Catholic University Liver Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Jong Young Choi
- The Catholic University Liver Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Seung Kew Yoon
- The Catholic University Liver Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul 06591, Republic of Korea
| | - Pil Soo Sung
- The Catholic University Liver Research Center, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, College of Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Correspondence: ; Tel.: +82-2258-7534; Fax: +82-2-3481-4025
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