A novel (288delC) mutation in exon 2 of GPIIb associated with type I Glanzmann's thrombasthenia

Novel Mutations in the GPIIb and GPIIIa Genes in Glanzmann Thrombasthenia

BACKGROUND: Glanzmann thrombasthenia (GT) is an inherited autosomal recessive platelet disorder characterized by a complete or partial lack, or mutation, of the GPIIb/IIIa complex (integrin α(IIb)β(3)) on the thrombocytes' surface, leading to a severe bleeding syndrome. MATERIAL AND METHODS: Molecular genetic analysis was performed in patients with suspected GT. The aim of the present study was the identification of new natural variants, their impact on platelet function, and their relation to the risk of bleeding. RESULTS: Expression of the platelet integrin α(IIb)β(3) was determined by flow cytometry. Mutations were identified through sequencing of cDNA and genomic DNA. In addition, platelet function studies (PAC-binding, aggregations) were implemented. The study included 25 patients revealing 13 mutations (GPIIb: n = 9; GPIIIa: n = 4). Two of the 13 mutations were previously described (T207I; L214P). The remaining mutations have not been published yet, whereas 1 mutation in 2 unrelated families was identical (3062 T→C). CONCLUSION: All patients with less than 25% of present α(IIb)β(3) have a medical history of bleeding.

A novel homozygous splice junction mutation in GPIIb associated with alternative splicing, nonsense-mediated decay of GPIIb-mRNA, and type II Glanzmann's thrombasthenia

This work reports the study of a patient suffering a bleeding disorder clinically diagnosed as Glanzmann's thrombasthenia (GT). Immunoblotting and flow cytometric analysis showed a low ( Collapse

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MESH Headings

• Alternative Splicing/genetics
• Codon, Nonsense
• Conserved Sequence/genetics
• Family Health
• Female
• Homozygote
• Humans
• Infant
• Mutation, Missense
• Platelet Glycoprotein GPIb-IX Complex/genetics
• Platelet Membrane Glycoproteins
• Point Mutation
• RNA Splice Sites/genetics
• RNA Stability/genetics
• RNA, Messenger/analysis
• Thrombasthenia/genetics

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Affiliation(s)

C González-Manchón Department of Pathophysiology and Human Molecular Genetics, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain.
E G Arias-Salgado
N Butta
G Martín
R B Rodríguez
I Elalamy
R Parrilla
R Favier

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Molecular basis of Glanzmann's Thrombasthenia and current strategies in treatment

Glanzmann Thrombasthenia, an exceptional inherited platelet disorder is characterized by a complete lack of platelet aggregation due to a defect in the alpha(IIb)beta(3) complex or to a qualitative abnormality of this complex. Advances in molecular biology have permitted to precise the molecular abnormality on alpha(IIb) or beta(3) genes responsible for the disease and have also contributed to a better knowledge of normal platelet physiology. Hemorrhages are the main clinical problem. Current principles of therapeutic management are proposed, with special reference to the risk of platelet alloimmunisation.

Management of the patient with coagulation disorders

Understanding normal haemostasis and the pathophysiology of its disorders is essential for providing optimal care and ensuring judicious usage of blood products, as is keeping abreast of novel therapeutic modalities in a rapidly evolving field. The growing availability of synthetic coagulation factors has (at least in the western hemisphere) helped to reduce morbidity and therapeutic complications, while expanding the indications and usage of these agents. Promising advances in gene therapy may indeed introduce a sea change in the next decade or two.