Case Report: A Novel Homozygous Variant Identified in a Chinese Patient With Benign Recurrent Intrahepatic Cholestasis-Type 1

Benign Recurrent Intrahepatic Cholestasis: Where Are We Now?

Benign recurrent intrahepatic cholestasis (BRIC) stands as a rare genetic contributor to cholestasis, aligning itself within the spectrum of inherited intrahepatic cholestasis syndromes, such as progressive familial intrahepatic cholestasis (PFIC) and intrahepatic cholestasis of pregnancy. Manifesting in infancy or early adulthood, BRIC is marked by recurrent episodes of jaundice accompanied by intense pruritus, enduring from weeks to years across the lifespan. Normal gamma-glutamyl transferase (GGT) levels are a characteristic laboratory finding. Initially considered unlikely to progress to chronic liver disease or cirrhosis, some reports suggest BRIC may evolve into a continuous and progressive form of cholestasis. Moreover, these recurrent cholestatic episodes significantly impact quality of life, and certain mutations elevate the risk of hepatobiliary malignancy. Between episodes, histological findings of centrilobular cholestasis and abnormal laboratory parameters revert to normal, potentially obviating the need for liver biopsy. This review focuses on the genetic aspects of BRIC, its pathophysiology, clinical presentation, and prognosis. Additionally, it outlines triggering factors and available treatment options.

Genetic alterations and molecular mechanisms underlying hereditary intrahepatic cholestasis

Hereditary cholestatic liver disease caused by a class of autosomal gene mutations results in jaundice, which involves the abnormality of the synthesis, secretion, and other disorders of bile acids metabolism. Due to the existence of a variety of gene mutations, the clinical manifestations of children are also diverse. There is no unified standard for diagnosis and single detection method, which seriously hinders the development of clinical treatment. Therefore, the mutated genes of hereditary intrahepatic cholestasis were systematically described in this review.

Improvement of cholestatic episodes in patients with benign recurrent intrahepatic cholestasis (BRIC) treated with rifampicin. A long-term follow-up

OBJECTIVE

Patients with benign recurrent intrahepatic cholestasis (BRIC) suffer from recurrent episodes of cholestatic jaundice. Treatment options remain limited and are mainly symptomatic. In case reports rifampicin, plasmapheresis, and nasobiliary drainage have been reported to be effective. In this case series, we present long-term experience indicating disease-modifying effects of non-invasive treatment with rifampicin for recurrent cholestasis in BRIC type 1 (BRIC1).

MATERIALS AND METHODS

We included all adult BRIC1 patients diagnosed and followed up at a single centre in Bergen, Norway. Data regarding clinical and biochemical features during BRIC attacks with and without rifampicin treatment were retrieved from medical journals and a data registry.

RESULTS

Five males with BRIC1 were included. Median age at diagnosis was 22 years (range 15-41). Together they had suffered from 65 cholestatic attacks (including four documented abortive attacks). Twenty-eight attacks were treated with rifampicin alone over the last 12 years; all cases showed symptomatic relief and reduction in the levels of bilirubin and alkaline phosphatase in blood. The attacks treated with rifampicin seemed to have shorter duration and were less likely to result in complications or hospitalization compared to attacks prior to the introduction of rifampicin. No side effects attributable to rifampicin were noted.

CONCLUSIONS

Episodic treatment of recurrent BRIC1 attacks with rifampicin seems to ameliorate severity and shorten the duration of attacks. Timely diagnosis and effective treatment are of major importance in BRIC, not only to decrease complications but also improving patients' quality of life.

Case Report: A Rare Heterozygous ATP8B1 Mutation in a BRIC1 Patient: Haploinsufficiency?

Benign recurrent intrahepatic cholestasis (BRIC) is an autosomal recessive disorder characterized by recurrent cholestasis. ATPase class I, type 8B, member 1 (ATP8B1) encodes familial intrahepatic cholestasis 1 (FIC1), which acts as a phosphatidylserine reversing enzyme in the tubule membrane of hepatocytes to mediate the inward translocation of phosphatidylserine (PS). At present, dozens of ATP8B1 pathogenic mutations have been identified that mainly cause BRIC1 and progressive familial intrahepatic cholestasis 1 (PFIC1). The diagnosis of BRIC1 is based on symptoms, laboratory tests, imaging, liver histology, and genetic testing. BRIC1 treatment seeks to prevent recurrence and reduce disease severity. At present, the main treatment methods include ursodeoxycholic acid (UDCA), rifampin, cholestyramine and haemofiltration, and endoscopic nasobiliary drainage (ENBD). Here, we report a 17-year-old patient with cholestasis who has a rare heterozygous ATP8B1 gene mutation (p.T888K). The patient was treated with UDCA, glucocorticoids and haemofiltration, after which bilirubin levels gradually returned to normal. This case was thought to be caused by an ATP8B1 heterozygous mutation, which may be related to haploinsufficiency (HI).

Case Report: A Rare Case of Benign Recurrent Intrahepatic Cholestasis-Type 1 With a Novel Heterozygous Pathogenic Variant of ATP8B1

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.