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Three novel missense mutations in the antithrombin III (AT3) gene causing recurrent venous thrombosis
D S Millar1, A I Wacey, J Ribando
1Charter Molecular Genetics Laboratory, Thrombosis Resarch Institute, London, UK.
Insights
Researchers identified novel mutations in the antithrombin III (AT3) gene linked to familial AT3 deficiency and thrombosis. These genetic changes impact antithrombin III protein synthesis and function, affecting blood clotting regulation.
Area of Science:
- Genetics
- Hematology
- Molecular Biology
Background:
- Familial antithrombin III (ATIII) deficiency is a genetic disorder predisposing individuals to recurrent venous thrombosis.
- Understanding the specific mutations in the AT3 gene is crucial for diagnosing and managing this condition.
Purpose of the Study:
- To identify and characterize the genetic mutations responsible for familial ATIII deficiency in seven unrelated patients.
- To correlate specific AT3 gene mutations with clinical phenotypes of ATIII deficiency (Type I and Type II).
Main Methods:
- Polymerase chain reaction (PCR) was employed to amplify specific regions of the AT3 gene.
- Direct sequencing was used to determine the nucleotide sequence and identify mutations within the AT3 gene of patients.
Main Results:
- Three novel mutations in the AT3 gene were discovered: Pro80-->Thr and His120-->Tyr, associated with reduced ATIII synthesis (Type I deficiency).
- A third novel mutation, Met251-->Ile, resulted in a dysfunctional ATIII protein (Type II deficiency), potentially affecting heparin binding or thrombin interaction.
- A novel polymorphism, Tyr158-->Cys, was identified in individuals of Scandinavian descent.
Conclusions:
- The study identified novel genetic variations in the AT3 gene contributing to familial ATIII deficiency and thrombosis.
- These findings enhance the understanding of genotype-phenotype correlations in ATIII deficiency, aiding in clinical diagnosis and genetic counseling.
Abstract:
The polymerase chain reaction and direct sequencing were used to determine the nature of the mutations in the antithrombin III (AT3) gene in seven unrelated patients with familial antithrombin III (ATIII) deficiency and recurrent venous thrombosis. Three novel mutations were found, two associated with a type I deficiency state (Pro80-->Thr and His120-->Tyr) manifesting reduced synthesis of ATIII. The other novel lesion (Met251-->Ile) was associated with a dysfunctional ATIII protein (type II ATIII deficiency) and is predicted to interfere either with a heparin-induced conformational change in the ATIII molecule or with docking to thrombin. A novel polymorphism (Tyr158-->Cys) was also found to occur in several individuals of Scandinavian origin.