Hyperhomocysteinaemia

Last updated: Friday, 06, August, 2010
Key InformationAppropriate Tests

Acquired, especially

Associations with increased risk of atherothrombotic and venous thromboembolic diseases are recognised.

  • Folate Deficiency (common)
  • Vitamins B12 and B6 deficiency
  • Smoking
  • Renal insufficiency
  • Hypothyroidism
  • Drug-induced (anticonvulsants, Methotrexate, Steroids, Cyclosporin)

Serum B12 and red cell folate, Urea and electrolytes and thyroid function.

Inherited, including

Methyltetrahydrofolate reductase thermolabile variant (MTHRF C677T mutation);

  • Homozygous individuals with the MTHFR C677T mutation have increased homocysteine levels In the presence of low folate stores
  • Associations between MTHFR C677T and coronary artery disease have recently been questioned

Homocystinuria (deficiency of cystathione beta-synthase).

  • The homozygous state is characterised by marfanoid habitus, lens dislocation and atherothrombotic events.
  • In comparison, the heterozygous state is characterised by normal homocysteine levels and a similar vascular risk when compared to the general population.

References:

Undas et al. Homocysteine and thrombosis: from basic science to clinical evidence, Thrombosis & Haemostasis 2005: 1994; 907-915

Lewis et al. Meta-analysis of MTHFR 6770 - T polymorphism and coronary heart disease: dose totality of evidence support causal role for homocysteine and preventative potential of folate, BMJ 2005; 331: 1053 - 1056