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GP1BB

Synonyms
BDPLT1, BS, CD42C, GPIBB, GPIbbeta
External resources
Summary
Platelet glycoprotein Ib (GPIb) is a heterodimeric transmembrane protein consisting of a disulfide-linked 140 kD alpha chain and 22 kD beta chain. It is part of the GPIb-V-IX system that constitutes the receptor for von Willebrand factor (VWF), and mediates platelet adhesion in the arterial circulation. GPIb alpha chain provides the VWF binding site, and GPIb beta contributes to surface expression of the receptor and participates in transmembrane signaling through phosphorylation of its intracellular domain. Mutations in the GPIb beta subunit have been associated with Bernard-Soulier syndrome, velocardiofacial syndrome and giant platelet disorder. The 206 amino acid precursor of GPIb beta is synthesized from a 1.0 kb mRNA expressed in plateletes and megakaryocytes. A 411 amino acid protein arising from a longer, unspliced transcript in endothelial cells has been described; however, the authenticity of this product has been questioned. Yet another less abundant GPIb beta mRNA species of 3.5 kb, expressed in nonhematopoietic tissues such as endothelium, brain and heart, was shown to result from inefficient usage of a non-consensus polyA signal in the neighboring upstream gene (SEPT5, septin 5). In the absence of polyadenylation from its own imperfect site, the SEPT5 gene produces read-through transcripts that use the consensus polyA signal of this gene.

Variant counts

The variants found in rare patients tested by 3billion are classified and counted according to ACMG guidelines. The variants with over 5% variant frequency in population genome databases ( gnomAD, dbSNP, etc) are excluded.

Pathogenic
0
Likely pathogenic
1
VUS
2,086
Likely benign
425
Benign
65

Patient phenotypes

Proportions of phenotypes among 1 patients carrying pathogenic or likely pathogenic variants on GP1BB gene are displayed below.

Phenotype class
Patients in 3billion (%)
Abnormality of the endocrine system
100%
Abnormal cellular phenotype
0%
Abnormality of blood and blood-forming tissues
0%
Abnormality of head or neck
0%
Abnormality of limbs
0%
Abnormality of metabolism homeostasis
0%
Abnormality of prenatal development or birth
0%
Abnormality of the breast
0%
Abnormality of the cardiovascular system
0%
Abnormality of the digestive system
0%
Abnormality of the ear
0%
Abnormality of the eye
0%
Abnormality of the genitourinary system
0%
Abnormality of the immune system
0%
Abnormality of the integument
0%
Abnormality of the musculoskeletal system
0%
Abnormality of the nervous system
0%
Abnormality of the respiratory system
0%
Abnormality of the thoracic cavity
0%
Abnormality of the voice
0%
Constitutional symptom
0%
Growth abnormality
0%
Neoplasm
0%

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