RESUMEN

Benign recurrent intrahepatic cholestasis is an autosomal recessive disorder presenting with intermittent episodes of cholestatic jaundice. The initial episode of benign recurrent intrahepatic cholestasis tends to occur within the first two decades of a patient's life. Episodes can occur unprompted but can often be precipitated by infections or pregnancy. We report an interesting case of a 13-year-old girl presented with recurrent intrahepatic cholestasis. The patient has a unique homozygous USP53 genetic mutation, the first patient to present with this mutation within the South Asian region. The patient was initially misdiagnosed as a case of autoimmune hepatitis, and when presenting to our set-up was diagnosed as a case of benign recurrent intrahepatic cholestasis. The patient has since been managed on medication and remains regular in follow-up, responding well to treatment.

RESUMEN

BACKGROUND: Benign recurrent intrahepatic cholestasis (BRIC) is a rare cause of cholestasis with recurrent episodes of jaundice and pruritus without extrahepatic bile duct obstruction. A mutation in the USP53 gene is known to cause BRIC-like cholestasis with normal serum gamma-glutamyltransferase (GGT) levels. CASE: We report a 16-year-old boy with recurrent episodes of cholestasis since 6 months of age with normal serum GGT levels. The liver biopsy showed ballooning degeneration of hepatocytes which is typical for BRIC, and intrahepatic and canalicular cholestasis with bilirubinostasis. We performed whole exome sequencing (WES) and identified a novel homozygous variant (NM_001371399.1:c.1558C > T) of the USP53 gene at exon 14 as the cause of BRIC. CONCLUSION: This is the first case of USP53 disease from Türkiye with a novel mutation in the USP53 gene. This novel identification of the mutation of c.1558C > T at exon 14 can provide elucidative data for those who work in the field of intrahepatic cholestasis. Our case suggests that USP53 disease must be kept in mind in patients with recurrent intrahepatic cholestasis with normal serum GGT levels.

Asunto(s)

Colestasis Intrahepática , Colestasis , Adolescente , Humanos , Masculino , Biopsia , Colestasis Intrahepática/diagnóstico , Colestasis Intrahepática/genética , Exones , Mutación , Proteasas Ubiquitina-Específicas

RESUMEN

Benign recurrent intrahepatic cholestasis type 1 (BRIC1) is a rare autosomal recessive disorder that is characterized by intermittent episodes of jaundice and intense pruritus and caused by pathogenic variants of adenosine triphosphatase phospholipid transporting 8B1 (ATP8B1). The presence of genetic heterogeneity in the variants of ATP8B1 is suggested. Herein, we describe a unique clinical course in a patient with BRIC1 and a novel heterozygous pathogenic variant of ATP8B1. A 20-year-old Japanese man experienced his first cholestasis attack secondary to elevated transaminase at 17 years of age. Laboratory examinations showed no evidence of liver injury caused by viral, autoimmune, or inborn or acquired metabolic etiologies. Since the patient also had elevated transaminase and hypoalbuminemia, he was treated with ursodeoxycholic acid and prednisolone. However, these treatments did not relieve his symptoms. Histopathological assessment revealed marked cholestasis in the hepatocytes, Kupffer cells, and bile canaliculi, as well as a well-preserved intralobular bile duct arrangement and strongly expressed bile salt export pump at the canalicular membrane. Targeted next-generation sequencing detected a novel heterozygous pathogenic variant of ATP8B1 (c.1429 + 2T > G). Taken together, the patient was highly suspected of having BRIC1. Ultimately, treatment with 450 mg/day of rifampicin rapidly relieved his symptoms and shortened the symptomatic period.

RESUMEN

Benign recurrent intrahepatic cholestasis (BRIC) is a rare hereditary cholestatic liver disorder. Accurate diagnosis and timely interventions are important in determining outcomes. Besides clinical and pathologic diagnosis, genetic study of BRIC remains limited. Here, we report a young man enduring recurrent jaundice and severe pruritus for 15 years. The increased level of direct bilirubin was the main biochemical abnormality, and the work-up for common causes of jaundice were unremarkable. Liver biopsy showed extensive cholestasis of hepatocytes in zone 3. The novel homozygous variant including c.1817T > C and p.I606T was detected on his ATP8B1gene. The patient was finally diagnosed with BRIC-1. His symptoms were relieved, and liver function tests returned to normal after taking ursodeoxycholic acid. This case provides a different perspective to the methodology employed when dealing with cases of jaundice and helping diagnose rare diseases.

RESUMEN

Benign recurrent intrahepatic cholestasis (BRIC) is a very rare autosomal recessive genetic disorder which presents with recurrent jaundice. We report the case of a young male with a history of methamphetamine use who presented with recurrent episodes of right upper quadrant abdominal pain, vomiting, dark urine, and pale stools. These symptoms always resolved within four weeks of presentation. During these episodes, the patient had a cholestatic pattern derangement of liver function tests with a normal gamma-glutamyl transferase (GGT). Workup for abnormal transaminases was unremarkable. A percutaneous liver biopsy obtained on the third visit was notable for a parenchymal lobule that exhibited slight Kupffer cell hyperplasia and subtle evidence of canalicular cholestasis. There was no evidence of cirrhosis, steatosis, hepatitis, or malignancy. Thus, a diagnosis of BRIC was made, and the patient was managed conservatively. Recognition of this rare entity is critical since its benign natural history is reassuring for the patient, and physicians can refrain from repetitive expansive and costly workups.

RESUMEN

The bile salt export pump (BSEP/ABCB11) is responsible for the transport of bile salts from hepatocytes into bile canaliculi. Malfunction of this transporter results in progressive familial intrahepatic cholestasis type 2 (PFIC2), benign recurrent intrahepatic cholestasis type 2 (BRIC2) and intrahepatic cholestasis of pregnancy (ICP). Over the past few years, several small molecular weight compounds have been identified, which hold the potential to treat these genetic diseases (chaperones and potentiators). As the treatment response is mutation-specific, genetic analysis of the patients and their families is required. Furthermore, some of the mutations are refractory to therapy, with the only remaining treatment option being liver transplantation. In this review, we will focus on the molecular structure of ABCB11, reported mutations involved in cholestasis and current treatment options for inherited BSEP deficiencies.

Asunto(s)

Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/genética , Ácidos y Sales Biliares/metabolismo , Colestasis Intrahepática/genética , Mutación , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP/metabolismo , Animales , Transporte Biológico , Colestasis Intrahepática/tratamiento farmacológico , Colestasis Intrahepática/metabolismo , Modelos Animales de Enfermedad , Regulación de la Expresión Génica , Humanos , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/uso terapéutico

RESUMEN

Drug-induced liver injury (DILI) is a matter of concern in the course of drug development and patient safety, often leading to discontinuation of drug-development programs or early withdrawal of drugs from market. Hepatocellular toxicity or impairment of bile acid (BA) metabolism, known as cholestasis, are the two clinical forms of DILI. Whole-body physiology-based modelling allows a mechanistic investigation of the physiological processes leading to cholestasis in man. Objectives of the present study were: (1) the development of a physiology-based model of the human BA metabolism, (2) population-based model validation and characterisation, and (3) the prediction and quantification of altered BA levels in special genotype subgroups and after drug administration. The developed physiology-based bile acid (PBBA) model describes the systemic BA circulation in humans and includes mechanistically relevant active and passive processes such as the hepatic synthesis, gallbladder emptying, transition through the gastrointestinal tract, reabsorption into the liver, distribution within the whole body, and excretion via urine and faeces. The kinetics of active processes were determined for the exemplary BA glycochenodeoxycholic acid (GCDCA) based on blood plasma concentration-time profiles. The robustness of our PBBA model was verified with population simulations of healthy individuals. In addition to plasma levels, the possibility to estimate BA concentrations in relevant tissues like the intracellular space of the liver enhance the mechanistic understanding of cholestasis. We analysed BA levels in various tissues of Benign Recurrent Intrahepatic Cholestasis type 2 (BRIC2) patients and our simulations suggest a higher susceptibility of BRIC2 patients toward cholestatic DILI due to BA accumulation in the liver. The effect of drugs on systemic BA levels were simulated for cyclosporine A (CsA). Our results confirmed the higher risk of DILI after CsA administration in healthy and BRIC2 patients. The presented PBBA model enhances our mechanistic understanding underlying cholestasis and drug-induced alterations of BA levels in blood and organs. The developed PBBA model might be applied in the future to anticipate potential risk of cholestasis in patients.

RESUMEN

Progressive familial intrahepatic cholestasis (PFIC) is a group of rare disorders which are caused by defect in bile secretion and present with intrahepatic cholestasis, usually in infancy and childhood. These are autosomal recessive in inheritance. The estimated incidence is about 1 per 50,000 to 1 per 100,000 births, although exact prevalence is not known. These diseases affect both the genders equally and have been reported from all geographical areas. Based on clinical presentation, laboratory findings, liver histology and genetic defect, these are broadly divided into three types-PFIC type 1, PFIC type 2 and PFIC type 3. The defect is in ATP8B1 gene encoding the FIC1 protein, ABCB 11 gene encoding BSEP protein and ABCB4 gene encoding MDR3 protein in PFIC1, 2 and 3 respectively. The basic defect is impaired bile salt secretion in PFIC1/2 whereas in PFIC3, it is reduced biliary phospholipid secretion. The main clinical presentation is in the form of cholestatic jaundice and pruritus. Serum gamma glutamyl transpeptidase (GGT) is normal in patients with PFIC1/2 while it is raised in patients with PFIC3. Treatment includes nutritional support (adequate calories, supplementation of fat soluble vitamins and medium chain triglycerides) and use of medications to relieve pruritus as initial therapy followed by biliary diversion procedures in selected patients. Ultimately liver transplantation is needed in most patients as they develop progressive liver fibrosis, cirrhosis and end stage liver disease. Due to the high risk of developing liver tumors in PFIC2 patients, monitoring is recommended from infancy. Mutation targeted pharmacotherapy, gene therapy and hepatocyte transplantation are being explored as future therapeutic options.

RESUMEN

BACKGROUND & AIMS: The bile salt export pump (BSEP, ABCB11) is essential for bile salt secretion at the canalicular membrane of liver cells. Clinical phenotypes associated with BSEP mutations are commonly categorized as benign recurrent intrahepatic cholestasis (BRIC-2) or progressive familial intrahepatic cholestasis (PFIC-2). METHODS: The molecular basis of BSEP-associated liver disease in a sibling pair was characterized by immunostaining, gene sequencing, bile salt analysis and recombinant expression in mammalian cells and yeast for localization and in vitro activity studies respectively. RESULTS: Benign recurrent intrahepatic cholestasis was considered in a brother and sister who both suffered from intermittent cholestasis since childhood. Gene sequencing of ABCB11 identified the novel missense mutation p.G374S, which is localized in the putative sixth transmembrane helix of BSEP. Liver fibrosis was present in the brother at the age of 18 with progression to cirrhosis within 3 years. Immunofluorescence of liver tissue showed clear canalicular BSEP expression; however, biliary concentration of bile salts was drastically reduced. In line with these in vivo findings, HEK293 cells showed regular membrane targeting of human BSEP(G374S), whereas in vitro transport measurements revealed a strongly reduced transport activity. CONCLUSIONS: The novel mutation p.G374S impairs transport function without disabling membrane localization of BSEP. While all other known BSEP mutations within transmembrane helices are associated with PFIC-2, the new p.G374S mutation causes a transitional phenotype between BRIC-2 and PFIC-2.

Asunto(s)

Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Cirrosis Hepática Biliar/genética , Modelos Moleculares , Conformación Proteica , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP , Transportadoras de Casetes de Unión a ATP/química , Secuencia de Bases , Ácidos y Sales Biliares/análisis , Western Blotting , Cromatografía Líquida de Alta Presión , Clonación Molecular , Cartilla de ADN/genética , Femenino , Técnica del Anticuerpo Fluorescente , Células HEK293 , Humanos , Cirrosis Hepática Biliar/patología , Masculino , Datos de Secuencia Molecular , Mutagénesis , Mutación Missense/genética , Análisis de Secuencia de ADN , Hermanos , Espectrometría de Masas en Tándem , Levaduras , Adulto Joven

RESUMEN

We report a young man presenting with jaundice and severe debilitating intrahepatic cholestasis 7 months before the diagnosis of Hodgkin's lymphoma. Serum gamma-glutamyl transferase (GGT) activity was not raised. Liver biopsy demonstrated deficiency of canalicular GGT and bile salt export pump expression, which suggested "benign" recurrent intrahepatic cholestasis. Direct sequencing of genomic DNA was therefore undertaken to look for mutations in ATP8B1 and ABCB11. Cholestasis and pruritus are well recognized presenting features of Hodgkin's lymphoma. However, striking in this case is that the intrahepatic cholestasis presented and resolved 7 months before the diagnosis. Furthermore, 4 polymorphisms were identified in ATP8B1 in this patient-c.696T > C (rs319438), c.811A > C (rs319438), c.2855G > A (rs1296811) and c.3454G > A (rs222581)-and two polymorphisms in ABCB11-c.1331T > C (rs2287622) and c.3084A > G (rs497692); 2 of which have been associated with intrahepatic cholestasis of pregnancy. We therefore postulate that these polymorphisms predisposed this patient to the development of intrahepatic cholestasis within the abnormal pro-inflammatory cytokine milieu typical for Hodgkin's lymphoma. This case shows for the first time that some polymorphisms in ABCB11 and ATP8B1 may predispose to the development of intrahepatic cholestasis in Hodgkin's lymphoma. It also demonstrates the importance of close clinical surveillance for the development of Hodgkin's lymphoma in patients presenting with unexplained intrahepatic cholestasis.

RESUMEN

A 56-year-old gentleman with benign recurrent intrahepatic cholestasis (BRIC) suffered from recurrent episodes of pruritus for over 40 years. The treatment prescribed, namely cholestyramine, was minimally effective. However, rifampin 150 mg b.i.d promptly and completely relieved his severe pruritus. The diagnosis of BRIC, being a rare condition, may go unrecognized. The severity of the lifelong episodes of intermittent cholestasis with pruritus in BRIC may be extremely distressing to the affected patient. Administration of rifampin during the acute episode of severe pruritus led to a marked improvement in his quality of life.