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Gene

HBB

hemoglobin subunit beta

Summary

Cytogenetic location
11p15.4
Coordinates
Chromosome 11: 5,225,464–5,227,071 (GRCh38)
Exons
3 exons across 1.6 kb
Protein
147 amino acids
Inheritance
Autosomal dominant Autosomal recessive
Also known as
CD113t-C, beta-globin
MANE Select transcript
ENST00000335295.4NM_000518.5
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

Reference genomeGRCh38

Positions on gene and variant pages follow this choice, in this browser.

Curated reports relevant to this gene

  • Hereditary Methaemoglobinaemia and Unstable Haemoglobins

    • Unstable Haemoglobin DiseaseAutosomal dominant

      A dominant condition caused by globin gene variants that make haemoglobin unstable, so it clumps inside red cells and causes haemolytic anaemia of varying severity.

      • ClinGen rates the link definitive
      • 1 GenCC submitter rates it definitive or strong
      What knowing changes

      Knowing about it helps avoid oxidant medicines that can worsen haemolysis and explains flare-ups during infections.

    • Heinz Body AnaemiaAutosomal dominant

      A dominant form of haemolytic anaemia in which unstable haemoglobin forms clumps (Heinz bodies) inside red cells.

      • 2 GenCC submitters rate it definitive or strong
      What knowing changes

      Knowing about it helps avoid oxidant medicines that can worsen haemolysis.

    • Hereditary Methaemoglobinaemia

      Raised methaemoglobin levels from birth, caused by recessive changes in CYB5R3 or CYB5A or by dominant haemoglobin M variants in the globin genes; type II CYB5R3 deficiency also causes severe developmental problems.

      • ClinGen rates the link definitive
      • 2 GenCC submitters rate it definitive or strong
      What knowing changes

      Knowing about it explains unexplained cyanosis and helps avoid medicines that raise methaemoglobin, such as dapsone, benzocaine and nitrites; methylene blue treats the enzyme forms but must not be given to people with G6PD deficiency.

  • Polycythemia

    • Familial Erythrocytosis 6 (High-Oxygen-Affinity Haemoglobin, HBB)Autosomal dominant

      A dominant form of inherited erythrocytosis caused by beta-globin variants that make haemoglobin hold on to oxygen too tightly, so the body makes more red cells to compensate.

      • ClinGen rates the link definitive
      • 4 GenCC submitters rate it definitive or strong
      What knowing changes

      Knowing the inherited cause avoids it being mistaken for polycythaemia vera or other acquired causes, and spares unnecessary investigations.

  • Sickle Cell Disease

    • Autosomal recessive

      A haemoglobinopathy caused by haemoglobin S, alone or with another HBB variant, leading to haemolytic anaemia and vaso-occlusive crises.

      • 3 GenCC submitters rate it definitive or strong
      What knowing changes

      Hydroxyurea (HbF induction), voxelotor, crizanlizumab, L-glutamine; curative hematopoietic stem cell transplantation and gene therapy (exagamglogene autotemcel)

  • Thalassaemia

    • Thalassemia

      A group of inherited haemoglobin disorders caused by reduced or absent synthesis of alpha- or beta-globin chains.

      • ClinGen rates the link definitive
      • 6 GenCC submitters rate it definitive or strong
      What knowing changes

      Transfusion and iron chelation (thalassemia major); hydroxyurea; betibeglogene autotemcel (Zynteglo) and exagamglogene autotemcel (Casgevy) gene therapy for transfusion-dependent disease; hematopoietic stem cell transplantation

    • Beta-Thalassaemia and Related DisordersAutosomal recessive

      Disorders of beta-globin production, including beta-thalassaemia, haemoglobin E-beta-thalassaemia, delta-beta-thalassaemia and haemoglobin Lepore, ranging from carrier states with mild anaemia to transfusion-dependent disease.

      • ClinGen rates the link definitive
      • 6 GenCC submitters rate it definitive or strong
      What knowing changes

      Carrier status is relevant to family planning, and affected people may need transfusions, iron chelation or newer treatments.

Inheritance

Autosomal dominant
One changed copy, from either parent, is enough. A parent who has one passes it on to each child with a one-in-two chance.
Autosomal recessive
It takes a changed copy from each parent. With one, you are a carrier and usually unaffected; when both parents are carriers, each child has a one-in-four chance of inheriting two.

How HBB is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
  • Variants with a page
Chromosome 11, with a bracket where HBB sits. HBB and 42 genes near it on chromosome 11, from 4,726,268 to 5,726,267.Chromosome 1111p15.4p15.5p15.4p15.3p15.2p15.1p14.3p14.2p14.1p13p12p11.2p11.12p11.11q11q12.1q12.2q12.3q13.1q13.2q13.3q13.4q13.5q14.1q14.2q14.3q21q22.1q22.2q22.3q23.1q23.2q23.3q24.1q24.2q24.3q254.8 Mb5 Mb5.2 Mb5.4 Mb5.6 MbMMP26: 4,704,784–4,992,431, forward strandOR51F1: 4,768,979–4,769,938, reverse strandOR51F1OR52R1: 4,803,433–4,804,380, reverse strandOR52R1OR51F2: 4,821,321–4,822,456, forward strandOR51F2OR51S1: 4,848,237–4,849,208, reverse strandOR51S1OR51T1: 4,881,819–4,882,883, forward strandOR51T1OR51A7: 4,903,783–4,909,462, forward strandOR51G2: 4,912,588–4,919,350, reverse strandOR51G2OR51G1: 4,923,374–4,924,339, reverse strandOR51G1OR51A4: 4,942,831–4,947,605, reverse strandOR51A4OR51A2: 4,954,772–4,955,713, reverse strandOR51A2OR51L1: 4,994,851–5,005,536, forward strandOR51L1OR52J3: 5,046,526–5,047,461, forward strandOR52J3OR52E2: 5,058,650–5,059,627, reverse strandOR52E2OR52E1: 5,069,572–5,070,497, forward strandOR52E1OR52A5: 5,128,776–5,138,356, reverse strandOR52A5OR52A1: 5,146,824–5,154,757, reverse strandOR52A1OR51V1: 5,199,735–5,200,682, reverse strandOR51V1HBB: 5,225,464–5,227,071, reverse strandHBBHBD: 5,232,678–5,243,698, reverse strandHBDHBG1: 5,248,204–5,249,859, reverse strandHBG1: 5,248,270–5,254,783, reverse strandHBG2: 5,253,188–5,505,605, reverse strand: 5,254,392–5,678,434, reverse strandHBE1: 5,268,345–5,505,652, reverse strandOR51B4: 5,301,014–5,301,946, reverse strandOR51B4OR51B5: 5,303,444–5,505,652, reverse strandOR51B2: 5,323,359–5,324,297, reverse strandOR51B2OR51B6: 5,351,508–5,352,446, forward strandOR51B6OR51M1: 5,383,812–5,393,263, forward strandOR51M1OR51Q1: 5,422,111–5,423,206, forward strandOR51I1: 5,440,570–5,441,514, reverse strandOR51I2: 5,449,323–5,456,518, forward strandOR52D1: 5,488,685–5,489,749, forward strandUBQLN3: 5,507,300–5,509,958, reverse strandUBQLNL: 5,514,393–5,518,431, reverse strandOR52H1: 5,544,489–5,548,540, reverse strandOR52H1OR52B6: 5,580,877–5,581,884, forward strandOR52B6TRIM6: 5,596,109–5,612,958, forward strandTRIM6TRIM6-TRIM34: 5,596,725–5,644,398, forward strandTRIM6-TRIM34TRIM34: 5,619,764–5,644,398, forward strandTRIM5: 5,663,195–5,938,619, reverse strandTRIM5TRIM22: 5,689,610–5,737,089, forward strandTRIM22Diagram of HBB: 3 exons on the reverse strand of chromosome 11Exon 3: 36 known disease-causing sitesExon 2: 53 known disease-causing sitesExon 1: 34 known disease-causing sitesExon 3: 5,225,464–5,225,726, 263 bases. 1 variant with a page in exon 3. List themExon 2: 5,226,577–5,226,799, 223 bases. 1 variant with a page in exon 2. List themExon 1: 5,226,930–5,227,071, 142 bases. 2 variants with a page in exon 1. List them3215′3′

Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

Nearby genes from Ensembl release 116, on GRCh38.

Exons make up 0.6 kb of the gene's 1.6 kb; 444 of those bases code for the protein.

How a genome test reads HBB

162

positions in HBB where ClinVar classes a change as pathogenic or likely pathogenic

11 of them (6.8%) fall in regions short reads find hard.

  • Low mappability (11 sites)Regions where 100 bp or 250 bp reads cannot be placed uniquely.

A whole genome covers all 1.6 kb of HBB, introns included, not only the 0.6 kb of exons.

Variants with a page (11)

The HBB variants with a page here, most review stars first. Each page describes ClinVar's public record of the variant, never a result.

VariantHGVS c.Exon or intronPosition (GRCh38)ClinVar classificationReview status
A28Sc.82G>TExon 15,226,940Pathogenic3 stars out of 4 reviewed by expert panel
c.*111A>GAATGAAExon 35,225,487Pathogenic3 stars out of 4 reviewed by expert panel
c.92+5G>CIVS1-5G>CIntron 15,226,925Pathogenic3 stars out of 4 reviewed by expert panel
c.93-21G>AIVS1-110G>AIntron 15,226,820Pathogenic3 stars out of 4 reviewed by expert panel
c.316-106C>GIVS2-745C>GIntron 25,225,832Pathogenic3 stars out of 4 reviewed by expert panel
c.316-146T>GIntron 25,225,872Pathogenic3 stars out of 4 reviewed by expert panel
c.316-197C>TIVS2-654C>TIntron 25,225,923Pathogenic3 stars out of 4 reviewed by expert panel
K18Xc.52A>TExon 15,226,970Pathogenic3 stars out of 4 reviewed by expert panel
rs339317465,227,099Pathogenic3 stars out of 4 reviewed by expert panel
rs33941377-87C>G5,227,158Pathogenic3 stars out of 4 reviewed by expert panel

See all 11 HBB variants →

Where this comes from

  • HGNC: the gene's symbol, name, other symbols and location.
  • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
  • GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
  • The ACMG secondary findings list, SF v3.2.
  • ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
  • Data release 2026.10.16-c6eea6bf.

Cite this page

APA

Dante Labs. (n.d.). HBB gene: hemoglobin subunit beta. Retrieved 16 October 2026, from https://dantelabs.com/genes/hbb

Vancouver

Dante Labs. HBB gene: hemoglobin subunit beta [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/hbb

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