Gene

GP1BA

glycoprotein Ib platelet subunit alpha

Cytogenetic location: 17p13.2
Coordinates: Chromosome 17: 4,932,277–4,935,023 (GRCh38)
Exons: 2 exons across 2.7 kb
Protein: 652 amino acids
Inheritance: Autosomal recessive
Also known as: HPA-2, CD42b, GPIbalpha
Previous symbols: GP1B
MANE Select transcript: ENST00000329125.6NM_000173.7
Locus type: gene with protein product

Very high
Confident
Low
Very low

Reference genomeGRCh38hg38

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

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Curated reports relevant to this gene

Hereditary Von Willebrand Disease
- Hereditary von Willebrand disease (VWD) is a hereditary bleeding disorder caused by a genetic anomaly leading to quantitative, structural or functional abnormalities of the Willebrand factor (von Willebrand factor; VWF). Two major groups of VWF deficiency have been defined: quantitative and partial (type 1) or total (type 3), and qualitative (type 2) with several subtypes (2A, 2B, 2M, 2N).
  - ClinGen rates the link definitive
  - 3 GenCC submitters rate it definitive or strong
  What knowing changes
  Type 1: desmopressin (DDAVP); type 2A: DDAVP trial or VWF concentrate; type 2B: VWF concentrate (DDAVP contraindicated); type 2M: DDAVP trial; type 2N: VWF/FVIII concentrate; type 3: VWF/FVIII concentrate; tranexamic acid for mucosal bleeding
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
  - 4 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 a genome test reads GP1BA

positions in GP1BA 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 2.7 kb of GP1BA, introns included, not only the 2.5 kb of exons.

Variants with a page (44)

The GP1BA 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
A318Pfs*17	c.952del	Exon 2	4,933,555	Likely pathogenic	3 stars out of 4 reviewed by expert panel
c.1077del		Exon 2	4,933,679	Likely pathogenic	3 stars out of 4 reviewed by expert panel
C81R	c.241T>C	Exon 2	4,932,845	Pathogenic	3 stars out of 4 reviewed by expert panel
C225R	c.673T>C	Exon 2	4,933,277	Likely pathogenic	3 stars out of 4 reviewed by expert panel
C225S	c.673T>A	Exon 2	4,933,277	Pathogenic	3 stars out of 4 reviewed by expert panel
D79Efs*2	c.236dup	Exon 2	4,932,839	Likely pathogenic	3 stars out of 4 reviewed by expert panel
D89Efs*63	c.266dup	Exon 2	4,932,869	Likely pathogenic	3 stars out of 4 reviewed by expert panel
E347X	c.1039G>T	Exon 2	4,933,643	Likely pathogenic	3 stars out of 4 reviewed by expert panel
E489Nfs*64	c.1465del	Exon 2	4,934,068	Likely pathogenic	3 stars out of 4 reviewed by expert panel
F208Lfs*48	c.624del	Exon 2	4,933,222	Likely pathogenic	3 stars out of 4 reviewed by expert panel

See all 44 GP1BA variants →

Traits linked to GP1BA

The Human Phenotype Ontology lists these as features of the rare conditions GP1BA can cause. Each trait's page lists the other genes linked to it.

Abnormality of blood and blood-forming tissues

Show 23 more traits

Abnormality of the nervous system

Abnormality of the eye

Laboratory abnormality

External links

Gene records

Transcript

Protein

Variants

Clinical

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.). GP1BA gene: glycoprotein Ib platelet subunit alpha. Retrieved 16 October 2026, from https://dantelabs.com/genes/gp1ba

Vancouver

Dante Labs. GP1BA gene: glycoprotein Ib platelet subunit alpha [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/gp1ba

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