Gene
GP9
glycoprotein IX platelet
- HGNC 4444(opens in a new tab)
- Ensembl gene ENSG00000169704(opens in a new tab)
- NCBI Gene 2815(opens in a new tab)
Summary
- Cytogenetic location
- 3q21.3
- Coordinates
- Chromosome 3: 129,060,779–129,062,406 (GRCh38)
- Exons
- 3 exons across 1.6 kb
- Protein
- 177 amino acids
- Inheritance
- Autosomal recessive
- Also known as
- CD42a, GPIX
- MANE Select transcript
- ENST00000307395.5NM_000174.5
- Locus type
- gene with protein product
Reference genomeGRCh38hg38
Positions on gene and variant pages follow this choice, in this browser.
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Inherited Platelet Function Disorders
- Bernard-Soulier SyndromeAutosomal recessive
A disorder caused by changes in GP1BA, GP1BB or GP9, in which platelets are large, reduced in number and cannot stick to damaged blood vessels; it is usually recessive, though milder dominant forms exist.
- ClinGen rates the link definitive
- 3 GenCC submitters rate it definitive or strong
What knowing changes
A correct diagnosis avoids it being mistaken for immune thrombocytopenia and treated unnecessarily.
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 GP9 is laid out
- Coding sequence
- Untranslated region
- Intron
- Direction of transcription
- Known disease-causing sites
- Variants with a page
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 1.6 kb; 534 of those bases code for the protein.
How a genome test reads GP9
23
positions in GP9 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 1.6 kb of GP9, introns included, not only the 0.9 kb of exons.
Variants with a page (16)
The GP9 variants with a page here, most review stars first. Each page describes ClinVar's public record of the variant, never a result.
| Variant | HGVS c. | Exon or intron | Position (GRCh38) | ClinVar classification | Review status |
|---|---|---|---|---|---|
| A159Rfs*77 | c.437_474dup | Exon 3 | 129,062,172 | Likely pathogenic | 3 stars out of 4 reviewed by expert panel |
| C24R | c.70T>C | Exon 3 | 129,061,809 | Likely pathogenic | 3 stars out of 4 reviewed by expert panel |
| C38R | c.112T>C | Exon 3 | 129,061,851 | Likely pathogenic | 3 stars out of 4 reviewed by expert panel |
| C89Y | c.266G>A | Exon 3 | 129,062,005 | Pathogenic | 3 stars out of 4 reviewed by expert panel |
| C135Y | c.404G>A | Exon 3 | 129,062,143 | Likely pathogenic | 3 stars out of 4 reviewed by expert panel |
| D102_P105delinsA | c.305_313del | Exon 3 | 129,062,043 | Likely pathogenic | 3 stars out of 4 reviewed by expert panel |
| F71C | c.212T>G | Exon 3 | 129,061,951 | Likely pathogenic | 3 stars out of 4 reviewed by expert panel |
| F71S | c.212T>C | Exon 3 | 129,061,951 | Pathogenic | 3 stars out of 4 reviewed by expert panel |
| G40Afs*43 | c.119del | Exon 3 | 129,061,854 | Likely pathogenic | 3 stars out of 4 reviewed by expert panel |
| L7P | c.20T>C | Exon 3 | 129,061,759 | Likely pathogenic | 3 stars out of 4 reviewed by expert panel |
Traits linked to GP9
The Human Phenotype Ontology lists these as features of the rare conditions GP9 can cause. Each trait's page lists the other genes linked to it.
External links
Gene records
Transcript
Protein
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
Dante Labs. (n.d.). GP9 gene: glycoprotein IX platelet. Retrieved 16 October 2026, from https://dantelabs.com/genes/gp9
Dante Labs. GP9 gene: glycoprotein IX platelet [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/gp9
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