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Gene

HEXA

hexosaminidase subunit alpha

Summary

Cytogenetic location
15q23
Coordinates
Chromosome 15: 72,340,924–72,376,014 (GRCh38)
Exons
14 exons across 35.1 kb
Protein
529 amino acids
Inheritance
Autosomal recessive
MANE Select transcript
ENST00000268097.10NM_000520.6
Locus type
gene with protein product

Reference genomeGRCh38

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

Curated reports relevant to this gene

  • Tay-Sachs Disease

    • Autosomal recessive

      GM2 gangliosidosis, variant B or Tay-Sachs disease is marked by accumulation of G2 gangliosides due to hexosaminidase A deficiency.

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

      No effective treatment for infantile Tay-Sachs (supportive/palliative care only); carrier screening and genetic counseling for reproductive risk reduction; substrate reduction therapy and gene therapy under clinical investigation

Broader groupings

  • Lysosomal Storage Disease

    • Lysosomal storage disease (other and unspecified types)

      One of 59 genes linked to it

      Covers lysosomal storage diseases without a dedicated report, such as Farber disease and other ASAH1-related disorders, prosaposin (PSAP) deficiencies, multiple sulfatase deficiency, mucopolysaccharidosis types IX and X, and Dorfman-Chanarin disease; inheritance varies by subtype, most often autosomal recessive.

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

Inheritance

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 HEXA is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
Chromosome 15, with a bracket where HEXA sits. HEXA and 14 genes near it on chromosome 15, from 71,858,469 to 72,858,468.Chromosome 1515q23p13p12p11.2p11.1q11.1q11.2q12q13.1q13.2q13.3q14q15.1q15.2q15.3q21.1q21.2q21.3q22.1q22.2q22.31q22.32q22.33q23q24.1q24.2q24.3q25.1q25.2q25.3q26.1q26.2q26.372 Mb72.2 Mb72.4 Mb72.6 Mb72.8 MbMYO9A: 71,822,291–72,118,577, reverse strandMYO9ASENP8: 72,114,258–72,143,692, forward strandSENP8GRAMD2A: 72,159,806–72,197,830, reverse strandGRAMD2APKM: 72,199,024–72,231,819, reverse strandPKMPARP6: 72,241,176–72,272,999, reverse strandPARP6: 72,266,746–72,319,946, reverse strand: 72,284,727–72,375,981, reverse strandCELF6: 72,284,727–72,320,622, reverse strandCELF6HEXA: 72,340,924–72,376,014, reverse strandHEXATMEM202: 72,398,302–72,408,367, forward strandTMEM202ARIH1: 72,474,308–72,602,987, forward strandARIH1GOLGA6B: 72,654,697–72,669,599, forward strandGOLGA6BHIGD2B: 72,675,791–72,686,621, reverse strandHIGD2BBBS4: 72,686,181–72,742,006, forward strandBBS4ADPGK: 72,735,951–72,785,846, reverse strandADPGKDiagram of HEXA: 14 exons on the reverse strand of chromosome 15Exon 14: 7 known disease-causing sitesExon 13: 14 known disease-causing sitesExon 12: 16 known disease-causing sitesExon 11: 28 known disease-causing sitesExon 10: 11 known disease-causing sitesExon 9: 14 known disease-causing sitesExon 8: 21 known disease-causing sitesExon 7: 20 known disease-causing sitesExon 6: 19 known disease-causing sitesExon 5: 19 known disease-causing sitesExon 4: 9 known disease-causing sitesExon 3: 9 known disease-causing sitesExon 2: 13 known disease-causing sitesExon 1: 35 known disease-causing sitesExon 14: 72,340,924–72,344,140, 3,217 basesExon 13: 72,345,446–72,345,550, 105 basesExon 12: 72,346,235–72,346,325, 91 basesExon 11: 72,346,527–72,346,710, 184 basesExon 10: 72,347,686–72,347,758, 73 basesExon 9: 72,348,048–72,348,134, 87 basesExon 8: 72,349,079–72,349,259, 181 basesExon 7: 72,350,518–72,350,650, 133 basesExon 6: 72,351,133–72,351,234, 102 basesExon 5: 72,353,068–72,353,178, 111 basesExon 4: 72,353,691–72,353,737, 47 basesExon 3: 72,355,559–72,355,624, 66 basesExon 2: 72,356,525–72,356,617, 93 basesExon 1: 72,375,720–72,376,014, 295 bases141210864215′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 4.8 kb of the gene's 35.1 kb; 1,590 of those bases code for the protein.

How a genome test reads HEXA

279

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

1 of them (0.4%) falls in a region short reads find hard.

  • Low mappability (1 site)Regions where 100 bp or 250 bp reads cannot be placed uniquely.
  • Segmental duplications (1 site)Copies of at least 1 kb sharing at least 90% identity with another part of the genome (paralogues, pseudogenes); reads may align to the wrong copy.

A whole genome covers all 35.1 kb of HEXA, introns included, not only the 4.8 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.). HEXA gene: hexosaminidase subunit alpha. Retrieved 16 October 2026, from https://dantelabs.com/genes/hexa

Vancouver

Dante Labs. HEXA gene: hexosaminidase subunit alpha [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/hexa

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