HLA-B

Chr 6

major histocompatibility complex, class I, B

Also known as: AS, B-4901, HLAB

NCBI Gene: 3106 ENSG00000234745 UniProt: P01889

HLA-B belongs to the HLA class I heavy chain paralogues. This class I molecule is a heterodimer consisting of a heavy chain and a light chain (beta-2 microglobulin). The heavy chain is anchored in the membrane. Class I molecules play a central role in the immune system by presenting peptides derived from the endoplasmic reticulum lumen. They are expressed in nearly all cells. The heavy chain is approximately 45 kDa and its gene contains 8 exons. Exon 1 encodes the leader peptide, exon 2 and 3 encode the alpha1 and alpha2 domains, which both bind the peptide, exon 4 encodes the alpha3 domain, exon 5 encodes the transmembrane region and exons 6 and 7 encode the cytoplasmic tail. Polymorphisms within exon 2 and exon 3 are responsible for the peptide binding specificity of each class one molecule. Typing for these polymorphisms is routinely done for bone marrow and kidney transplantation. Hundreds of HLA-B alleles have been described. [provided by RefSeq, Jul 2008]

GeneReviews Research

GeneReviews ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProtStevens-Johnson syndrome

UniProtSpondyloarthropathy 1

Active trials

636

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

0.91

LOEUF

Mechanism· predicted

📖

GeneReview available — HLA-B

Authoritative clinical overview · Recommended first read

Open GeneReview ↗

Some data sources returned errors (1)

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?

0.91LOEUF

pLI 0.000

Z-score 1.85

OE 0.54 (0.33–0.91)

Tolerant

Typical tolerance to LoF variation

Missense Constraint?

-0.01Z-score

OE missense 1.00 (0.89–1.13)

196 obs / 195.6 exp

Tolerant

Tolerant to missense variation

Observed / Expected Ratios?

LoF OE?0.54 (0.33–0.91)

0≤0.351.4

Missense OE?1.00 (0.89–1.13)

0≤0.61.4

Synonymous OE?0.98

0≤1.21.6

LoF obs/exp: 10 / 18.6Missense obs/exp: 196 / 195.6Syn Z: 0.13

ClinVar Variant Classifications

0 submitted variants in ClinVar

ClinVar

Protein Context — Lollipop Plot

HLA-B · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

External Resources

Links to major genomics databases and tools

Franklin by Genoox

AI-powered variant curation and clinical analysis

DECIPHER

Genomic variants and phenotypes in rare disease patients

📖

GeneReview available — HLA-B

Authoritative clinical overview · NCBI Bookshelf · Recommended first read

Open GeneReview ↗

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

AutophagyGalectinsHIV Infections

Study of Autophagy and the Effects of GALIG Gene Products in HIV-1 Infected Patients Who Are Under Antiretroviral Therapy Since Primary-infection, Chronic Phase, or Never Treated.

RECRUITING

NCT04160455Centre Hospitalier Régional d'OrléansStarted 2019-11-07

expression of a panel

Kidney Transplant

Alloreactive Memory B Lymphocytes and Anti-HLA Sensitization

RECRUITING

NCT07011238University Hospital, RouenStarted 2023-04-17

Patients meeting HLA immunization criteria

Liver DiseasesLiver CancerLiver Cirrhosis

CRISPR-Edited HLA Donor Liver Transplant to Reduce Rejection

RECRUITING

NCT07053488Phase PHASE1, PHASE2AMERICAN ORGAN TRANSPLANT AND CANCER RESEARCH INSTITUTE LLCStarted 2025-06-01