title: Role of Hyperhomocysteinemia and Methylene Tetrahydrofolate Reductase C677T Polymorphism in Idiopathic Portal Vein Thrombosis.
abstract: OBJECTIVE
  Portal vein thrombosis (PVT) is a rare and life-threatening vascular disorder characterized by obstruction or narrowing of the portal vein. Hyperhomocysteinemia and methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism has been studied in PVT patients with conflicting results. In the present study the association of hyperhomocysteinemia and MTHFR C677T polymorphism with PVT risk was investigated in Iranians.
  
  
  METHODS
  Our study population consisted of 10 idiopathic PVT patients and 80 healthy control subjects matched for age and sex. MTHFR C677T polymorphism was genotyped by the polymerase chain reaction technique combined with restriction enzyme fragment length polymorphism (PCR-RFLP) technique and plasma total homocysteine (tHcy) levels were determined by enzyme immunoassay method.
  
  
  RESULTS
  Mean plasma tHcy levels were significantly higher in PVT patients (20.2±6.8) than control subjects (10.9±4.7) (P=0.001). Moreover, plasma tHcy levels were significantly higher in 677T allele carriers relative to 677C allele carriers in both PVT patients (P=0.01) and control subjects (P=0.03). Neither homozygote nor heterozygote genotypes of MTHFR C677T polymorphism correlated significantly with PVT risk (P>0.05). Moreover, MTHFR C677T polymorphism didn't increase the risk of PVT under dominant (CT+TT vs. CC) or recessive (TT vs. CC+CT) genetic models analyzed (P>0.05). The difference in frequency of minor 677T allele between PVT patients and control subjects was not statistically significant (P>0.05).
  
  
  CONCLUSIONS
  Based on the current study, we suggest that hyperhomocysteinemia constitutes a significant and common risk factor for PVT. Also, MTHFR C677T polymorphism is not a risk factor for PVT but is a contributing factor for elevated plasma tHcy levels.
authors.affiliation: Cellular and Molecular Research Centre, Zahedan University of Medical Sciences, Zahedan.
authors.forename: Habib
authors.initials: H
authors.lastname: Ghaznavi
authors.affiliation: Department of Medical Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Soheili
authors.affiliation: Iranian Blood Transfusion Organization, Tehran.
authors.forename: Shahram
authors.initials: S
authors.lastname: Samiei
authors.affiliation: Department of Laboratory Sciences, Faculty of Paramedical Sciences, Zanjan University of Medical Sciences, Zanjan, Iran.
authors.forename: Mohammad Soleiman
authors.initials: MS
authors.lastname: Soltanpour
keywords: Genetic polymorphism; Homocysteine; Methylene tetrahydrofolate reductase; Portal vein thrombosis