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Increased prevalence of methylenetetrahydrofolate reductase C677T variant in patients with inflammatory bowel disease, and its clinical implications
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  1. N Mahmuda,
  2. A Molloya,
  3. J McPartlina,
  4. R Corballya,
  5. A S Whiteheadc,
  6. J M Scottb,
  7. D G Weira
  1. aDepartment of Clinical Medicine, Trinity College, University of Dublin, Ireland, bDepartment of Biochemistry, Trinity College, University of Dublin, Ireland, cDepartment of Genetics, Trinity College, University of Dublin, Ireland
  1. Professor D G Weir, Department of Clinical Medicine, Trinity College Dublin, Trinity Centre for Health Sciences, St James’s Hospital, Dublin 8, Ireland.

Abstract

BACKGROUND Inflammatory bowel disease (IBD) is associated with an increased incidence of thromboembolic disease. Hyperhomocysteinaemia (hyper-tHcy), a condition associated with the C677T variant of 5,10-methylenetetrahydrofolate reductase (MTHFR), is linked with an increased incidence of thromboembolic disease. Hyper-tHcy has been reported in patients with IBD.

AIMS To assess the prevalence of the C677T MTHFR genotype and the contribution of this genotype to hyper-tHcy in patients with IBD.

METHODS Patients with established IBD (n=174) and healthy controls (n=273) were studied. DNA samples were genotyped for the MTHFR (C677T) mutation. Subjects were categorised as homozygous for the thermolabile variant (TT), heterozygous for wild type and variant (CT), or homozygous for the wild type (CC).

RESULTS Plasma homocysteine concentrations were significantly higher in patients with IBD than in healthy controls. A total of 17.5% of ulcerative colitis and 16.8% of Crohn’s disease patients were homozygous for the C677T variant compared with 7.3% of controls. Homozygosity (TT) for the variant was associated with higher plasma tHcy levels in patients with IBD and in healthy controls. When all subjects who were TT for the variant were excluded, median plasma tHcy was still significantly higher in IBD than controls. Plasma vitamin B12 levels were lower in patients with IBD irrespective of MTHFR genotype.

CONCLUSIONS There is an association between the thermolabile MTHFR C677T variant and IBD. This accounts in part for the raised plasma tHcy found in patients with IBD and may contribute to the increased incidence of thromboembolic complications. All patients with IBD should receive low dose folic acid and vitamin B12 therapy to protect against the thromboembolic complications of raised tHcy.

  • methylenetetrahydrofolate reductase
  • C677T variant
  • inflammatory bowel disease
  • Abbreviations used in this paper

    tHcy
    homocysteine
    IBD
    inflammatory bowel disease
    MTHFR
    5,10-methylenetetrahydrofolate reductase
  • Statistics from Altmetric.com

  • Abbreviations used in this paper

    tHcy
    homocysteine
    IBD
    inflammatory bowel disease
    MTHFR
    5,10-methylenetetrahydrofolate reductase
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