GENE REFERENCE / HGNC:4948

HLA-DRB1

major histocompatibility complex, class II, DR beta 1

protein-coding gene6p21.32Gene information

What does this gene do?

The HLA-DRB1 gene provides instructions for making a protein that plays a critical role in the immune system. The HLA-DRB1 gene is part of a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish between the body's own proteins and the proteins made by foreign invaders such as viruses and bacteria.

The HLA complex is the human version of the major histocompatibility complex (MHC), a gene family that occurs in many species. The HLA-DRB1 gene belongs to a group of MHC genes called MHC class II. MHC class II genes provide instructions for making proteins that are present on the surface of certain immune system cells. These proteins attach to protein fragments (peptides) outside the cell. MHC class II proteins display these peptides to the immune system. If the immune system recognizes the peptides as foreign, it triggers a response to attack the invading viruses or bacteria.

The protein produced from the HLA-DRB1 gene, called the beta chain, attaches (binds) to another protein called the alpha chain, which is produced from the HLA-DRA gene. Together, they form a functional protein complex called the HLA-DR antigen-binding heterodimer. This complex displays foreign peptides to the immune system to trigger an immune response.

The wide variety within MHC class II genes allows the immune system to react to a range of foreign invaders. Researchers have identified hundreds of different versions of the HLA-DRB1 gene, each of which is given a particular number (such as HLA-DRB1*04:01).

Source: MedlinePlus, National Library of Medicine. Source publication: 2025-09-05. Source review: 2025-09.

ClinGen reviews

We found no matching ClinGen review in the data used here. This does not rule out a link between the gene and a condition.

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: 157
Submissions for variants in or overlapping this gene: 792
Submissions explicitly reporting this gene: 766
Alleles reported pathogenic / likely pathogenic: 3
VariationIDs with uncertain significance: 8
VariationIDs with conflicting classifications: 2

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 HLA-DRB1?

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 3 alleles in HLA-DRB1 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 HLA-DRB1.

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

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