GENE REFERENCE / HGNC:4827

HBB

hemoglobin subunit beta

protein-coding gene11p15.4Gene information

What does this gene do?

The HBB gene provides instructions for making a protein called beta-globin. Beta-globin is a component (subunit) of a larger protein called hemoglobin, which is located inside red blood cells. In adults, hemoglobin typically consists of four protein subunits: two subunits of beta-globin and two subunits of a protein called alpha-globin, which is produced from another gene called HBA. Each of these protein subunits is attached (bound) to an iron-containing molecule called heme; the iron in the center of each heme can bind to one oxygen molecule. The hemoglobin within red blood cells binds to oxygen molecules in the lungs. The red blood cells then travel through the bloodstream and deliver oxygen to tissues throughout the body.

Source: MedlinePlus, National Library of Medicine. Source publication: 2025-04-03. Source review: 2024-03.

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
beta-thalassemia HBB/LCRBMONDO:0013517 · Evaluated 2023-04-26	Autosomal recessive	DefinitiveGeneral Gene Curation Expert Panel
hemoglobin M diseaseMONDO:0018023 · Evaluated 2024-03-28	Autosomal dominant	DefinitiveGeneral Gene Curation Expert Panel
obsolete sickle cell disease and related diseasesMONDO:0017146 · Evaluated 2023-08-23	Autosomal recessive	DefinitiveGeneral Gene Curation Expert Panel
unstable hemoglobin diseaseMONDO:0020459 · Evaluated 2024-02-28	Autosomal dominant	DefinitiveGeneral Gene Curation Expert Panel
dominant beta-thalassemiaMONDO:0011381 · Evaluated 2023-03-22	Autosomal dominant	DefinitiveGeneral Gene Curation Expert Panel
erythrocytosis, familial, 6MONDO:0054801 · Evaluated 2023-09-27	Autosomal dominant	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: 1,944
Submissions for variants in or overlapping this gene: 4,541
Submissions explicitly reporting this gene: 4,479
Alleles reported pathogenic / likely pathogenic: 467
VariationIDs with uncertain significance: 296
VariationIDs with conflicting classifications: 105

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 HBB?

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 467 alleles in HBB 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 HBB.

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

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