8. Glanzmann’s Thrombasthenia (GT)
- Men and women affected equally
- Genetic defect located on chromosome 17
- Impaired platelet aggregation is the hallmark of GT
12. Methods
20 patients (GT)
Blood sampling, DNA extraction, and analysis by spectrophotometer
Amplification by touch-down PCR
Conformation Sensitive Gel
Electrophoresis heteroduplex PCR
DNA Sequencing
17. Results and Discussion
Mutation Identification
* Point mutations and polymorphism in GPIIb/IIIa complex
* Missense and nonsense mutations cause premature
termination or splice site defects.
* Ligand binding activity, rate of the complex expression, and the
receptor activation impaired depending on the site of mutation
18. Discussion
* 3 novel mutations and 2 novel polymorphisms were recognized
during the examination of entire coding regions of ITGA2B and ITGB3
genes.
* Frameshift mutations resulted in premature termination
or splice site alteration.
- The beginning of exon 9 of ITGB3 and exon 1 of ITGA2B.
- The middle of exon 12 of ITGB3
19. Discussion
* 2 novel synonymous polymorphisms (silent mutation)
- exon 10 of IGTB3 no effect on plt (aggregation or adhesion)
* Substitution mutation on exon 5 of IGTB3 disrupt
GPIIb/IIIa structure and LBA prevents plts aggregation
* Type I GT no GPIIb/IIIa expression on their plts.
* Another polymorphism (missense gene alteration) in the
extracellular domain of B3
20. Conclusion
* The platelet membrane glycoprotein IIb/IIIa complex mutations
lead to Glanzmann's thrombasthenia. A large variety of mutations
and polymorphisms are responsible for the aberrant expression and
defective activity of this heterodimeric complex.
* Mutation screening was analyzed using conformation-sensitive
gel electrophoresis heteroduplex PCR, and DNA sequencing.