GENE REFERENCE / HGNC:4932

HLA-B

major histocompatibility complex, class I, B

protein-coding gene6p21.33Gene information

What does this gene do?

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

HLA is the human version of the major histocompatibility complex (MHC), a gene family that occurs in many species. Genes in this complex are categorized into three basic groups: class I, class II, and class III. In humans, the HLA-B gene and two related genes, HLA-A and HLA-C, are the main genes in MHC class I.

MHC class I genes provide instructions for making proteins that are present on the surface of almost all cells. On the cell surface, these proteins are bound to protein fragments (peptides) that have been exported from within the cell. MHC class I proteins display these peptides to the immune system. If the immune system recognizes the peptides as foreign (such as viral or bacterial peptides), it responds by triggering the infected cell to self-destruct.

The HLA-B gene has many possible variations, that result in the production of proteins that differ by changes in at least one protein building block (amino acid). This variety allows each person's immune system to react to a wide range of foreign invaders. Most HLA-B gene alleles are rare, while others do not affect protein function or change the structure of the protein. Hundreds of versions (alleles) of the HLA-B gene are known, each of which is given a particular number (such as HLA-B27). Closely related alleles are categorized together; for example, more than 60 very similar alleles are subtypes of HLA-B27. These subtypes are designated as HLA-B*2701 to HLA-B*2763.

Source: MedlinePlus, National Library of Medicine. Source publication: 2025-09-08. Source review: 2022-03.

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: 141
Submissions for variants in or overlapping this gene: 434
Submissions explicitly reporting this gene: 412
Alleles reported pathogenic / likely pathogenic: 1
VariationIDs with uncertain significance: 5
VariationIDs with conflicting classifications: 1

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-B?

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 1 allele in HLA-B 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-B.

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

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