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Gene

BTK

Bruton tyrosine kinase

Summary

Cytogenetic location
Xq22.1
Coordinates
Chromosome X: 101,349,450–101,386,191 (GRCh38)
Exons
19 exons across 36.7 kb
Protein
659 amino acids
Inheritance
X-linked recessive
Also known as
ATK, XLA, PSCTK1
Previous symbols
AGMX1, IMD1
MANE Select transcript
ENST00000308731.8NM_000061.3
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

  • Agammaglobulinaemia (XLA and Autosomal Forms)

    • X-linked agammaglobulinaemia (Bruton type, BTK)X-linked recessive

      Absent B cells and very low antibody levels caused by changes in BTK, usually affecting boys from a few months of age.

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

      Lifelong immunoglobulin replacement, prompt treatment of infections and avoiding live vaccines prevent most serious complications.

Broader groupings

  • Other Inborn Errors of Immunity

    • Inborn error of immunity

      One of 114 genes linked to it

      Inherited disorders of the immune system caused by changes in single genes, affecting how the body fights infection or regulates inflammation.

      • ClinGen rates the link definitive
      • 3 GenCC submitters rate it definitive or strong
    • 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.

      • ClinGen rates the link definitive
      • 3 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

X-linked recessive
The change is on the X chromosome, so one copy affects males, who have one X, while females with one are usually carriers. A carrier mother passes it on to each child with a one-in-two chance.

How BTK is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
Chromosome X, with a bracket where BTK sits. BTK and 18 genes near it on chromosome X, from 100,867,821 to 101,867,820.Chromosome XXq22.1p22.33p22.32p22.31p22.2p22.13p22.12p22.11p21.3p21.2p21.1p11.4p11.3p11.23p11.22p11.21p11.1q11.1q11.2q12q13.1q13.2q13.3q21.1q21.2q21.31q21.32q21.33q22.1q22.2q22.3q23q24q25q26.1q26.2q26.3q27.1q27.2q27.3q28101 Mb101.2 Mb101.4 Mb101.6 Mb101.8 MbNOX1: 100,843,324–100,874,464, reverse strandNOX1XKRX: 100,886,924–100,929,433, reverse strandXKRXARL13A: 100,969,708–100,990,831, forward strandARL13ATRMT2B: 100,973,670–101,052,135, reverse strandTRMT2BTMEM35A: 101,078,870–101,096,367, forward strandTMEM35ACENPI: 101,098,150–101,166,126, forward strandCENPIDRP2: 101,219,723–101,264,502, forward strandDRP2TAF7L: 101,268,253–101,293,057, reverse strandTAF7LTIMM8A: 101,320,050–101,349,001, reverse strandTIMM8ABTK: 101,349,450–101,386,191, reverse strandBTKRPL36A: 101,390,824–101,396,155, forward strandRPL36ARPL36A-HNRNPH2: 101,391,011–101,412,297, forward strandRPL36A-HNRNPH2GLA: 101,393,273–101,408,012, reverse strandGLAHNRNPH2: 101,408,114–101,414,778, forward strandARMCX4: 101,418,269–101,535,551, forward strandARMCX1: 101,550,411–101,554,704, forward strandARMCX1ARMCX6: 101,615,118–101,618,011, reverse strandARMCX6ARMCX3: 101,622,797–101,627,843, forward strandARMCX3ARMCX2: 101,654,024–101,659,924, reverse strandARMCX2Diagram of BTK: 19 exons on the reverse strand of chromosome XExon 19: 6 known disease-causing sitesExon 18: 25 known disease-causing sitesExon 17: 21 known disease-causing sitesExon 16: 9 known disease-causing sitesExon 15: 20 known disease-causing sitesExon 14: 7 known disease-causing sitesExon 13: 7 known disease-causing sitesExon 12: 8 known disease-causing sitesExon 11: 8 known disease-causing sitesExon 10: 5 known disease-causing sitesExon 9: 3 known disease-causing sitesExon 8: 8 known disease-causing sitesExon 7: 3 known disease-causing sitesExon 6: 15 known disease-causing sitesExon 5: 11 known disease-causing sitesExon 4: 8 known disease-causing sitesExon 3: 10 known disease-causing sitesExon 2: 13 known disease-causing sitesExon 19: 101,349,450–101,349,956, 507 basesExon 18: 101,353,194–101,353,351, 158 basesExon 17: 101,353,870–101,353,988, 119 basesExon 16: 101,354,630–101,354,694, 65 basesExon 15: 101,356,052–101,356,268, 217 basesExon 14: 101,356,784–101,356,955, 172 basesExon 13: 101,357,509–101,357,583, 75 basesExon 12: 101,358,310–101,358,437, 128 basesExon 11: 101,358,617–101,358,696, 80 basesExon 10: 101,359,293–101,359,347, 55 basesExon 9: 101,360,088–101,360,150, 63 basesExon 8: 101,360,568–101,360,755, 188 basesExon 7: 101,362,173–101,362,240, 68 basesExon 6: 101,362,561–101,362,689, 129 basesExon 5: 101,369,998–101,370,079, 82 basesExon 4: 101,371,633–101,371,701, 69 basesExon 3: 101,374,536–101,374,634, 99 basesExon 2: 101,375,144–101,375,314, 171 basesExon 1: 101,386,062–101,386,191, 130 bases191816141210864215′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 2.6 kb of the gene's 36.7 kb; 1,980 of those bases code for the protein.

How a genome test reads BTK

226

positions in BTK 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 36.7 kb of BTK, introns included, not only the 2.6 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.). BTK gene: Bruton tyrosine kinase. Retrieved 16 October 2026, from https://dantelabs.com/genes/btk

Vancouver

Dante Labs. BTK gene: Bruton tyrosine kinase [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/btk

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