GENE REFERENCE / HGNC:45

ABCB4

ATP binding cassette subfamily B member 4

protein-coding gene7q21.12Gene information

What does this gene do?

The ABCB4 gene (also known as MDR3) provides instructions for making a protein that helps move certain fats called phospholipids across the membranes of liver cells. The protein essentially flips the phospholipids from the inside to the outside of the cells. The protein then releases the phospholipids into a digestive fluid called bile. Outside the liver cells, in the bile duct, phospholipids attach (bind) to bile acids, which are the component of bile that digests fats. Large amounts of bile acids are potentially harmful to cells. When bile acids are bound to phospholipids, they are less toxic.

Source: MedlinePlus, National Library of Medicine. Source publication: 2025-01-31. Source review: 2024-05.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
progressive familial intrahepatic cholestasis type 3MONDO:0011214 · Evaluated 2022-11-23	Autosomal recessive	DefinitiveGeneral Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 1,637
Submissions for variants in or overlapping this gene: 2,846
Submissions explicitly reporting this gene: 2,712
Alleles reported pathogenic / likely pathogenic: 288
VariationIDs with uncertain significance: 728
VariationIDs with conflicting classifications: 110

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about ABCB4?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 288 alleles in ABCB4 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in ABCB4.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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