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ABCB4

Chr 7q21.12

ATP binding cassette subfamily B member 4

Aliases:
MDR2, PFIC-3, GBD1
MANE:
ENST00000649586.2
OMIM: 171060 ↗NCBI: 5244 ↗Ensembl ↗

Annotations refreshed 1 month ago.

Predicted protein structure

Clinical relevance (Genomics England PanelApp)

Diagnostic Grade (Green)

  • Cholestasis

    BOTH monoallelic and biallelic, autosomal or pseudoautosomal

  • Likely inborn error of metabolism

    BOTH monoallelic and biallelic, autosomal or pseudoautosomal

  • Neonatal cholestasis

    BOTH monoallelic and biallelic, autosomal or pseudoautosomal

  • Undiagnosed metabolic disorders

    BOTH monoallelic and biallelic, autosomal or pseudoautosomal

  • Childhood onset dystonia, chorea or related movement disorder

Disease associations (Open Targets)

  • progressive familial intrahepatic cholestasis type 3

    0.85

  • cholestasis, intrahepatic, of pregnancy 3

    0.80

  • cholelithiasis

    0.79

  • Intrahepatic cholestasis of pregnancy

    0.74

  • gallbladder disorder

    0.74

  • gallbladder disease 1

    0.73

  • intrahepatic cholestasis

    0.69

  • progressive familial intrahepatic cholestasis

    0.68

  • gallstones

    0.64

  • Cholecystitis

    0.62

Score is the Open Targets composite evidence score (0-1). Higher = stronger gene-disease association.

Protein function (UniProt)

Phosphatidylcholine translocator ABCB4

Energy-dependent phospholipid efflux translocator that acts as a positive regulator of biliary lipid secretion. Functions as a floppase that translocates specifically phosphatidylcholine (PC) from the inner to the outer leaflet of the canalicular membrane bilayer into the canaliculi of hepatocytes. Translocation of PC makes the biliary phospholipids available for extraction into the canaliculi lumen by bile salt mixed micelles and therefore protects the biliary tree from the detergent activity of bile salts (PubMed:17523162, PubMed:21820390, PubMed:23468132, PubMed:24594635, PubMed:24723470, PubMed:24806754, PubMed:31873305, PubMed:7957936, PubMed:8898203, PubMed:9366571). Plays a role in the recruitment of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and sphingomyelin (SM) molecules to nonraft membranes and to further enrichment of SM and cholesterol in raft membranes in hepatocytes (PubMed:23468132). Required for proper phospholipid bile formation (By similarity). Indirectly involved in cholesterol efflux activity from hepatocytes into the canalicular lumen in the presence of bile salts in an ATP-dependent manner (PubMed:24045840). Promotes biliary phospholipid secretion as canaliculi-containing vesicles from the canalicular plasma membrane (PubMed:28012258, PubMed:9366571). In cooperation with ATP8B1, functions to protect hepatocytes from the deleterious detergent activity of bile salts (PubMed:21820390). Does not confer multidrug resistance (By similarity)

Diseases associated with ABCB4

Curated MONDO disease pages that list ABCB4 among their top associated genes.

Data sources: HGNC (CC BY 4.0), AlphaFold (CC BY 4.0, Jumper et al. Nature 2021), Genomics England PanelApp (CC BY 4.0), ClinGen, Open Targets (CC0), UniProt.

Not for sole clinical decision-making. Always verify against primary sources.