Skip to content
Use your HSA or FSA funds

Gene

B2M

beta-2-microglobulin

Summary

Cytogenetic location
15q21.1
Coordinates
Chromosome 15: 44,711,517–44,718,145 (GRCh38)
Exons
4 exons across 6.6 kb
Protein
119 amino acids
Inheritance
Autosomal dominant
MANE Select transcript
ENST00000648006.3NM_004048.4
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 Amyloidosis

    • Autosomal dominant

      Hereditary amyloidosis refers to a group of inherited conditions that make up one of the subtypes of amyloidosis. Hereditary amyloidosisis characterized by the deposit of an abnormal protein called amyloid in multiple organs of the body where it should not be, which causes disruption of organ tissue structure and function. In hereditary amyloidosis, amyloid deposits most often occur in tissues of the heart, kidneys, and nervous system. While symptoms of hereditary amyloidosis may appear in childhood, most individuals do not experience symptoms until adulthood. There are many types of hereditary amyloidosis associated with different gene mutations and abnormal proteins. The most common type of hereditary amyloidosis is transthyretin amyloidosis (ATTR), a condition in which the amyloid deposits are most often made up of the transthyretin protein which is made in the liver. Other examplesof hereditary amyloidosis include, but are not limited to, apolipoprotein AI amyloidosis (A ApoAI), gelsolin amyloidosis (A Gel), lysozyme amyloidosis (A Lys), cystatin C amyloidosis (A Cys), fibrinogen Aα-chain amyloidosis (A Fib), and apolipoprotein AII amyloidosis (A ApoAII).

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

      Tafamidis (kinetic stabilizer), patisiran (RNAi), vutrisiran (RNAi), inotersen (antisense), liver transplantation

Broader groupings

  • Other Inborn Errors of Immunity

    • Immunodeficiency Disease

      One of 170 genes linked to it

      Disease in which there is a deficiency or defect in the mechanisms of immunity, either cellular or humoral.

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

      HSCT for SCID and severe PIDs; immunoglobulin replacement (IVIG/SCIG) for antibody deficiencies; leniolisib (Joenja, FDA 2023) for APDS; gene therapy for ADA-SCID; abatacept for CTLA4/LRBA deficiency; prophylactic antibiotics; G-CSF for CGD

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.

How B2M is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
Chromosome 15, with a bracket where B2M sits. B2M and 13 genes near it on chromosome 15, from 44,214,831 to 45,214,830.Chromosome 1515q21.1p13p12p11.2p11.1q11.1q11.2q12q13.1q13.2q13.3q14q15.1q15.2q15.3q21.1q21.2q21.3q22.1q22.2q22.31q22.32q22.33q23q24.1q24.2q24.3q25.1q25.2q25.3q26.1q26.2q26.344.4 Mb44.6 Mb44.8 Mb45 Mb45.2 MbGOLM2: 44,288,699–44,415,758, forward strandGOLM2CTDSPL2: 44,427,187–44,529,038, forward strandCTDSPL2EIF3J: 44,537,055–44,564,631, forward strandEIF3JSPG11: 44,554,436–44,663,688, reverse strandSPG11PATL2: 44,665,723–44,711,384, reverse strandPATL2B2M: 44,711,517–44,718,145, forward strandB2MTRIM69: 44,728,986–44,767,829, forward strandTRIM69TERB2: 44,956,687–44,979,229, forward strandTERB2SORD: 45,023,116–45,077,185, forward strandSORDDUOX2: 45,092,650–45,114,185, reverse strandDUOX2DUOXA2: 45,114,325–45,118,421, forward strandDUOXA2DUOXA1: 45,117,364–45,130,611, reverse strandDUOXA1DUOX1: 45,129,450–45,165,576, forward strandDUOX1SHF: 45,165,572–45,201,175, reverse strandSHFDiagram of B2M: 4 exons on the forward strand of chromosome 15Exon 1: 2 known disease-causing sitesExon 1: 44,711,517–44,711,613, 97 basesExon 2: 44,715,423–44,715,701, 279 basesExon 3: 44,716,329–44,716,356, 28 basesExon 4: 44,717,607–44,718,145, 539 bases12345′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 0.9 kb of the gene's 6.6 kb; 360 of those bases code for the protein.

How a genome test reads B2M

4

positions in B2M where ClinVar classes a change as pathogenic or likely pathogenic

None of them falls in a region short reads find hard.

A whole genome covers all 6.6 kb of B2M, introns included, not only the 0.9 kb of exons.

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.). B2M gene: beta-2-microglobulin. Retrieved 16 October 2026, from https://dantelabs.com/genes/b2m

Vancouver

Dante Labs. B2M gene: beta-2-microglobulin [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/b2m

One test. A lifetime of answers.

From $449Free shipping · Results in 6–8 weeks

Get my Genome Test