ABCB4 : ATP binding cassette subfamily B member 4

ABCB4 Gene: The Phospholipid Transporter

Introduction

The ABCB4 gene, also known as MDR3, plays a vital role in the liver's ability to process and excrete certain fats. Here's an informative exploration of this gene, its functions, associated diseases, and recent research.

Description

The ABCB4 gene provides instructions for creating a protein called P-glycoprotein, which is embedded in the membranes of liver cells. P-glycoprotein acts as a transporter, flipping phospholipids, a type of fat molecule, from the inside to the outside of cells. These phospholipids are then released into bile, a digestive fluid produced by the liver.

Role in Bile Formation

In the bile duct, outside the liver cells, phospholipids bind to bile acids, the main components of bile. Bile acids are essential for digesting fats. However, high levels of bile acids can be toxic to cells. By binding to phospholipids, P-glycoprotein reduces the toxicity of bile acids and facilitates their excretion from the body.

Associated Diseases

Mutations in the ABCB4 gene can lead to a condition called progressive familial intrahepatic cholestasis type 3 (PFIC3), a liver disease characterized by the accumulation of bile acids in the liver. PFIC3 can cause liver damage, cirrhosis, and eventually liver failure.

Did you Know ?

Approximately 1 in 50,000 people worldwide are affected by PFIC3, making it a relatively rare condition. However, it is the most common form of PFIC and accounts for about 20% of all cases.