Hyperhomocysteinemia and C677T MTHFR Genotype in Patients With Retinal Vein Thrombosis

Sottilotta, Gianluca; Siboni, Simona Maria; Latella, Caterina; Oriana, Vincenzo; Romeo, E.; Santoro, Rita; Consonni, Dario; Lombardo, Vincenzo

doi:10.1177/1076029609348644

Cited by 30 publications

(15 citation statements)

References 21 publications

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“…Although inherited thrombophilia may be associated with an unusual location of thrombosis, we did not detect a significant association in cases of MTHFR polymorphisms, concordant with other studies (51)(52)(53).…”

Section: Discussionsupporting

confidence: 82%

The Importance of Homozygous Polymorphisms of Methylenetetrahydrofolate Reductase Gene in Romanian Patients with Idiopathic Venous Thromboembolism

Popp¹,

Fodor²

2013

Balkan Med J

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IntroductionVenous thromboembolism (VTE) is a multifactorial disease, usually the result of the interaction between a genetic background predisposing to hypercoagulability and acquired risk factors. Although considered idiopathic in 25-50% of cases, investigations may detect a cause in over 80% of the patients with VTE (1). Previous studies have shown that an underlying thrombophilia could be found in about half of patients with a first episode of idiopathic VTE (1, 2). Among the "traditional" thrombophilia factors (such as protein C, protein S or antithrombin III deficiency, Factor V Leiden or Prothrombin G20210A mutations), methylenetetrahydrofolate reductase (MTHFR) polymorphisms associated with hyperhomocysteinemia have recently raised interest. The MTHFR gene encodes the enzyme MTHFR, which regulates the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, the substrate for remethylation of homocysteine to methionine. The MTHFR gene is located on the short (p) arm of chromosome 1 at position 36.3. There are two common polymorphisms of the MTHFR gene: the MTHFR 677 CT polymorphism resulting in the substitution of alanine to valine at codon 222 (AlaVal) and the MTHFR 1298 AC polymorphism, resulting in a glutamine to alanine substitution (GluAla). The MTHFR C677T polymorphism, especially in the homozygous state, leads to decreased enzyme activity and hyperhomocysteinemia, whereas the MTHFR A1298C polymorphism presents a less well-defined effect, with a lesser decrease of the enzyme function.The prevalence of the T allele varies among races and ethnic groups: it is more common in Caucasians and Asians (30%) compared to African Americans (11%) (3, 4). In Europe, the lowest frequency is found in Finland (25.1%) and the Netherlands (27.4%) and the highest in Italy (45%; 47.3% in Sicily), France (34%-36%), Hungary (33.7%) and Spain (33%) (5-7). The incidence of the MTHFR C677T polymorphism in the general population is about 45% and 15% for heterozygous and homozygous genotypes, respectively. The prevalence of homozygotes for the MTHFR 677TT polymorphism in Europe varies between 5 and 15%; the heterozygous MTHFR C677T genotype presents the highest prevalence in Italy (44%) and the lowest in Norway (28%) (3,4,8,9).The role of MTHFR polymorphisms in VTE is controversial: some authors have shown an association between the MTHFR C677T polymorphism and VTE (10-14), whereas others have proven the contrary (15)(16)(17)

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Section: Discussionsupporting

confidence: 82%

The Importance of Homozygous Polymorphisms of Methylenetetrahydrofolate Reductase Gene in Romanian Patients with Idiopathic Venous Thromboembolism

Popp¹,

Fodor²

2013

Balkan Med J

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“…Two common polymorphisms in MTHFR gene, the C677T and A1298C, have been associated with decreased MTHFR activity and elevated plasma tHcy levels [10]. The association between MTHFR C677T polymorphism with RVT has been studied extensively with conflicting results [6,[11][12][13][14][15][16]. However, studies regarding the association of MTHFR A1298C polymorphism with RVT are limited.…”

Section: Introductionmentioning

confidence: 99%

Plasma homocysteine levels, methylene tetrahydrofolate reductase A1298C gene polymorphism and risk of retinal vein thrombosis

Ghaznavi

Soheili

Samiei

et al. 2016

Blood Coagulation &Amp; Fibrinolysis

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There are limited data regarding the role of methylene tetrahydrofolate reductase (MTHFR) A1298C polymorphism and hyperhomocysteinemia as risk factors for retinal vein thrombosis (RVT) in Iranians. This study aimed to examine a possible association between fasting plasma total homocysteine (tHcy) levels, MTHFR A1298C polymorphism and RVT development in Iranian patients. Our study population consisted of 73 patients with a diagnosis of RVT (52.7 ± 16.2 years) and 73 age and sex-matched healthy controls (49.1 ± 14.6 years). Genotyping for the MTHFR A1298Cpolymorphism was conducted by PCR-RFLP technique and plasma tHcy levels were measured by an enzyme immunoassay method. Fasting plasma tHcy levels were 20.29 ± 8.5 μmol/l in RVT patients and 10.9 ± 3.1 μmol/l in control subjects. The number of cases with abnormal tHcy values (hyperhomocysteinemia) was significantly higher in the RVT patients than control subjects (P = 0.0001). The prevalence of MTHFR 1298CC homozygote genotype was similar in RVT patients and controls (17.8 vs.15.1%, P = 0.45). There were no significant differences in genotype distribution of MTHFR A1298C polymorphism between males and females in both RVT patients and controls (P > 0.05). The frequency of the 1298C allele was 39.1 and 35.6% in patients and controls, respectively, and did not differ significantly between them (P = 0.23). Moreover, heterozygote and homozygote genotypes in the RVT patients had significantly higher abnormal tHcy values than corresponding genotypes in control subjects (P < 0.001). Our study demonstrated that hyperhomocysteinemia but not homozygosity for MTHFR A1298C polymorphism is a significant risk factor for RVT in the Iranian population.

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“…RVO is classified as central (CRVO) and branch RVO (BRVO) depending on the site of occlusion. The prevalence of BRVO (0.6 - 1.6%) is greater than that of CRVO (0.1 - 0.4%) [13,14]. The pathogenesis is multifactorial and poorly understood.…”

Section: Discussionmentioning

confidence: 99%

Relationship between angiotensin I-converting enzyme insertion/deletion gene polymorphism and retinal vein occlusion

et al. 2014

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To evaluate the association between angiotensin I-converting enzyme insertion/deletion (ACE I/D) gene polymorphism and retinal vein occlusion (RVO). A total of 80 patients with retinal vein occlusion who was admitted to the Eye Department of Kartal Training and Research Hospital between 2008 and 2011, and 80 subjects were enrolled in this retrospective case–control study. Patients who experienced RVO within one week to six months of study enrolment were included, and those with coronary artery diseases, prior myocardial infarction history and coagulation disturbances were excluded from the study. The diagnosis was made by ophthalmoscopic fundus examination and fluorescein angiography. The ACE gene I/D polymorphism was determined by polymerase chain reaction, and the ACE gene was classified into three types: I/I, I/D and D/D. In multivariate logistic regression analysis, ACE D/D genotype (p = 0.035), diabetes-mellitus (p = 0.019) and hypertension (p = 0.001) were found to be independent predictive factors for RVO. The results of the present study reveal that ACE D/D polymorphism is an independent predictive factor for RVO. However, one cannot definitely conclude that ACE gene polymorphism is a risk factor for retinal vein occlusion.

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Hyperhomocysteinemia and C677T MTHFR Genotype in Patients With Retinal Vein Thrombosis

Abstract: our study suggests that HHcy is a possible risk factor for RVT development, while no association was found between RVT and the C677T MTHFR genotype.

Cited by 30 publications

References 21 publications

The Importance of Homozygous Polymorphisms of Methylenetetrahydrofolate Reductase Gene in Romanian Patients with Idiopathic Venous Thromboembolism

The Importance of Homozygous Polymorphisms of Methylenetetrahydrofolate Reductase Gene in Romanian Patients with Idiopathic Venous Thromboembolism

Plasma homocysteine levels, methylene tetrahydrofolate reductase A1298C gene polymorphism and risk of retinal vein thrombosis

Relationship between angiotensin I-converting enzyme insertion/deletion gene polymorphism and retinal vein occlusion

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