Benign Recurrent Intrahepatic Cholestasis Type 1 with Novel Nonsense Mutations in the ATP8B1 Gene

Abstract

Benign recurrent intrahepatic cholestasis (BRIC) is a group of genetically heterogeneous autosomal recessive liver disorders characterized by recurrent episodes of jaundice and pruritus. BRIC is divided into two groups, BRIC type 1 (BRIC1) and BRIC type 2 (BRIC2), caused by mutations in the ATP8B1 and ABCB11 genes. We show that novel nonsense mutations in ATP8B1 (c.2989G>A, c.1547T>A) are the cause of BRIC1. A 16-year-old girl presented with severe jaundice. Acute and chronic liver diseases with infectious (hepatitis virus), metabolic, and autoimmune etiologies were excluded. Imaging revealed normal intra- and extra-hepatic bile ducts. Liver biopsy revealed severe intrahepatic bile stasis with bile plugs. She had similar symptoms at the age of 0 years. The BRIC criteria were satisfied, and ATP8B1 and ABCB11 gene analyses performed. Surprisingly, novel nonsense variants of the ATP8B1 gene (c.2989G>A and c.1547T>A) in heterozygosis were found, which were identified in each of her parents. Therefore, the compound heterozygote was thought to cause BRIC1 in these patients. Genetic mutations that differ from those already known may help diagnose patients with BRIC.

Keywords

• atp8b1
• autosomal recessive liver disease
• benign recurrent intrahepatic cholestasis