Fattore II

Graefes Arch Clin Exp Ophthalmol. 2001 Apr;239(4):251-6.

The heterozygous 20210 G/A genotype prevalence in patients affected by central and branch retinal vein occlusion: a pilot study.

Incorvaia C, Parmeggiani F, Costagliola C, Lamberti G, Ferraresi P, Bernardi F, Sebastiani A.

Department of Ophthalmology, University of Ferrara, Corso Giovecca 203, 44100 Ferrara, Italy. sbd@dns.unife.it

BACKGROUND: Several inherited conditions have been associated with an increased or decreased incidence of retinal vein occlusion (RVO). The A allele in the 20210 G/A prothrombin gene has been found to be associated with systemic venous thrombosis. The aim of this study has been to verify the prevalence of this mutation in patients affected by central RVO (CRVO) or branch RVO (BRVO). METHODS: A retrospective study was carried out on 100 consecutive patients suffering from RVO, more than 50 years old, unaffected by systemic diseases known to be associated with markedly increased RVO occurrence. We determined the frequency of this mutation by performing mutagenised amplification of exon 14 followed by restriction analysis of the amplified DNA fragment. RESULTS: The overall frequency of prothrombin 20210A allele in RVO patients was 6.0%. All heterozygous patients had suffered from CRVO. In this study subgroup, the frequency of the 20210 G/A prothrombin heterozygosis was 12.0%. The difference in the frequency of this the genetic variant between the CRVO and BRVO groups was statistically significant. None of the conventional RVO risk factors were statistically related to the occurrence of the disease in either the CRVO or the BRVO subgroup. CONCLUSION: The prevalence of the prothrombin 20210A mutation observed in CRVO patients is significantly higher than in the normal Italian population. Moreover, the prevalence is significantly greater in CRVO than in BRVO patients. These results raise the possibility that the prothrombin 20210A variant may be considered as a risk factor for CRVO.

PMID: 11450488 [PubMed - indexed for MEDLINE]

Am J Ophthalmol. 1999 Aug;128(2):247-8.

Idiopathic central retinal vein occlusion in a thrombophilic patient with the heterozygous 20210 G/A prothrombin genotype.

Incorvaia C, Lamberti G, Parmeggiani F, Ferraresi P, Calzolari E, Bernardi F, Sebastiani A.

Department of Ophthalmology, University of Ferrara, Italy.

PURPOSE: To report the occurrence of monolateral central retinal vein occlusion in a patient with heterozygous 20210 G/A prothrombin genotype, known to be associated with high thrombophilic risk. METHODS: A monolateral central retinal vein occlusion was diagnosed in a 71-year-old woman, who had suffered from a deep vein thrombosis in her left leg at the age of 36 years. Mutations of the genes involved in the coagulation process were investigated by DNA polymerase chain reaction. RESULT: DNA analysis showed the patient to be heterozygous for the prothrombin 20210 G/A genetic variation. CONCLUSION: The 20210 G/A prothrombin gene mutation may be associated with central retinal vein occlusion.

PMID: 10458191 [PubMed - indexed for MEDLINE]

Thromb Haemost. 1998 Apr;79(4):706-8.

Geographic distribution of the 20210 G to A prothrombin variant.

Rosendaal FR, Doggen CJ, Zivelin A, Arruda VR, Aiach M, Siscovick DS, Hillarp A, Watzke HH, Bernardi F, Cumming AM, Preston FE, Reitsma PH.

Department of Clinical Epidemiology, Leiden University Medical Centre, The Netherlands. Rosendaal@rullf2.leidenuniv.nl

A variant in prothrombin (clotting factor II), a G to A transition at nucleotide position 20210, has recently been shown to be associated with the prothrombin plasma levels and the risk of both venous and arterial thrombosis. The purpose of this study was to investigate the prevalence of carriership of this mutation in various populations. We combined data from 11 centres in nine countries, where tests for this mutation had been performed in groups representing the general population. We calculated an overall prevalence estimate, by a precision-weighted method, and, since the distribution of the prevalences did not appear homogeneous, by an unweighted average of the prevalences. We examined differences in the prevalences by geographical location and ethnic background as a possible explanation for the heterogeneity. Among a total of 5527 individuals who had been tested, 111 heterozygous carriers of the 20210A mutation were found. The prevalence estimates varied from 0.7 to 4.0 between the centres. The overall prevalence estimate was 2.0 percent (CI95 1.4-2.6%). The variation around the summary estimate appeared more than was expected by chance alone, and this heterogeneity could be explained by geographic differences. In southern Europe, the prevalence was 3.0 percent (CI95 2.3 to 3.7%), nearly twice as high as the prevalence in northern Europe (1.7%, CI95 1.3 to 2.2%). The prothrombin variant appeared very rare in individuals from Asian and African descent. The 20210A prothrombin variant is a common abnormality, with a prevalence of carriership between one and four percent. It is more common in southern than in northern Europe. Since this distribution within Europe is very different to that of another prothrombotic mutation (factor V Leiden or factor V R506Q), founder effects are the most likely explanation for the geographical distribution of both mutations.

PMID: 9569177 [PubMed - indexed for MEDLINE]

Arterioscler Thromb Vasc Biol. 1997 Nov;17(11):2418-22.

The heterozygous 20210 G/A prothrombin genotype is associated with early venous thrombosis in inherited thrombophilias and is not increased in frequency in artery disease.

Ferraresi P, Marchetti G, Legnani C, Cavallari E, Castoldi E, Mascoli F, Ardissino D, Palareti G, Bernardi F.

Dipartimento di Biochimica e Biologia Molecolare, Università, Ferrara, Italy.

A genetic variation in the 3'-untranslated region of the prothrombin mRNA (20210 G/A) has recently been reported to be associated with elevated plasma prothrombin levels and with an increased incidence of venous thrombosis. We determined the frequency of this mutation, the detection of which was improved by allele-specific amplification of exon 14 and by denaturing gradients (denaturing gradient gel electrophoresis), in cohorts of patients affected by venous thrombosis (n = 132) or by coronary or cerebrovascular diseases (n = 195) and in normal subjects from various populations. An overlapping frequency of the heterozygous genotype (4%) was found in normal subjects from Italy and Cyprus, and no carrier was detected in 40 subjects of Indian or Somali origin. The 20210 GA heterozygous genotype was not increased in frequency in patients with arterial disease. In contrast, the GA genotype was associated (P = .007) with venous thrombosis both in simple heterozygotes (16%) with a family history of thrombosis as well as in double heterozygotes (14%) for other known thrombophilic defects. A synergic interaction between the prothrombin 20210 GA genotype and the factor V Leiden mutation, both potentially affecting the prothrombinase complex, was suggested by the early onset of thrombosis (median age 22 years) in doubly heterozygous patients. The association of the 20210 A allele with higher prothrombin levels was confirmed in the Italian population. However, the prothrombin assay does not allow an efficient preselection of patients for the DNA analysis.

PMID: 9409210 [PubMed - indexed for MEDLINE]