From: Elizabeth M. Van Cott, M.D., and Michael Laposata, M.D., Ph.D., "Coagulation." In: Jacobs DS et al, ed. The Laboratory Test Handbook, 5th Edition. Lexi-Comp, Cleveland, 2001; 327-358.
Index of Tests
Prothrombin G20210A Mutation [CO005900]
Abstract This mutation is a common hereditary predisposition
to venous thrombosis. DNA-based methods, such as the polymerase
chain reaction (PCR)-based assay, are used to determine the presence
of a specific mutation at nucleotide position 20210 in the prothrombin
Specimen Whole blood
Container Varies with laboratory
Collection Routine venipuncture
Storage Instructions Do not centrifuge or freeze specimen.
Store at 4degrees C or room temperature.
Turnaround Time Several days or longer (depending on how
often test batches are performed)
Reference Interval Normal: prothrombin G20210A mutation not
Use The test identifies individuals who have the prothrombin
G20210A mutation. The results indicate whether an affected individual
is heterozygous or homozygous for the mutation. The heterozygous
form of the mutation is present in 2.3% of the general population
and 6.2% of patients with venous thrombosis.1 It is present
in 18% of cases of familial venous thrombosis.2
Methodology Commonly, polymerase chain reaction (PCR). The
prothrombin G20210A mutation is a point mutation in which the guanine
at nucleotide position 20210 is replaced by an adenine. The nucleotide
change also allows the introduction of a new Hind III restriction
site during PCR.2 To perform the test, DNA is isolated
from whole blood and the mutation site is amplified by PCR. The
PCR product is digested with Hind III and then subjected to agarose
gel electrophoresis to separate the DNA bands based on size. The
presence of a Hind III site at position 20210 can be determined
by the pattern of DNA bands detected on the gel. The presence of
a Hind III site at position 20210 indicates the presence of the
prothrombin G20210A mutation. Heterozygotes and homozygotes can
be specifically identified.
Additional Information The mutation involves a guanine to
adenine transition at nucleotide position 20210 in an untranslated
region of the gene. It is associated with elevated prothrombin levels
and an increased risk for venous thrombosis.2,3,4 Individuals heterozygous for the prothrombin G20210A mutation have
a two- to threefold increased risk for venous thrombosis.1 Homozygous individuals likely have an even higher risk for venous
thrombosis. The risk for venous thrombosis is further increased
in the presence of a second risk factor.5,6 Some studies
have shown an increased risk for arterial thrombosis7 while other studies have not.8 It is possible that an
increased risk for arterial thrombosis exists only when additional
risk factors for arterial thrombosis are also present.9
1. van der Meer FJ, Koster T, Vandenbroucke JP, et al, "The Leiden
Thrombophilia Study (LETS),"Thromb Haemost, 1997, 78(5):631-5.
2. Poort SR, Rosendaal FR, Reitsma PH, et al, "A Common Genetic
Variation in the 3'-Untranslated Region of the Prothrombin Gene
Is Associated With Elevated Plasma Prothrombin Levels and an Increase
in Venous Thrombosis,"Blood, 1996, 88(10):3698-703.
3. Soria JM, Almasy L, Souto JC, et al, "Linkage Analysis Demonstrates
That the Prothrombin G20210A Mutation Jointly Influences Plasma
Prothrombin Levels and Risk of Thrombosis,"Blood, 2000, 95(9):2780-5.
4. Cattaneo M, Chantarangkul V, Taioli E, et al, "The G20210A Mutation
of the Prothrombin Gene in Patients With Previous First Episodes
of Deep-Vein Thrombosis: Prevalence and Association With Factor
V G1691A, Methylenetetrahydrofolate Reductase C677T and Plasma Prothrombin
Levels,"Thromb Res, 1999; 93(1):1-8
5. Martinelli I, Taioli E, Bucciarelli P, et al, "Interaction Between
the G20210A Mutation of the Prothrombin Gene and Oral Contraceptive
Use in Deep Vein Thrombosis,"Arterioscler Thromb Vasc Biol,
6. Martinelli I, Sacchi E, Landi G, et al, "High Risk of Cerebral-Vein
Thrombosis in Carriers of a Prothrombin Gene Mutation and in Users
of Oral Contraceptives,"N Engl J Med, 1998, 338(25):1793-7.
7. Franco RF, Trip MD, ten Cate H, et al, "The 20210 G/A Mutation
in the 3'-Untranslated Region of the Prothrombin Gene and the Risk
for Arterial Thrombotic Disease,"Br J Haematol, 1999, 104(1):50-4.
8. Ridker PM, Hennekens CH, and Miletich JP, "G20210A Mutation
in Prothrombin Gene and Risk of Myocardial Infarction, Stroke, and
Venous Thrombosis in a Large Cohort of U.S. Men,"Circulation,
9. Inbal A, Freimark D, Modan B, et al, "Synergistic Effects of
Prothrombotic Polymorphisms and Atherogenic Factors on the Risk
of Myocardial Infarction in Young Males,"Blood, 1999, 93(7):2186-90.
De Stefano V, Chiusolo P, Paciaroni K, et al, "Prothrombin G20210A
Mutant Genotype Is a Risk Factor for Cerebrovascular Ischemic Disease
in Young Patients,"Blood, 1998, 91(10) :3562-3565.
Eikelboom JW, Baker RI, Parsons R, et al, "No Association Between
the 20210 G/A Prothrombin Gene Mutation and Premature Coronary Artery
Disease,"Thromb Haemost, 1998, 80(6):878-880.