Hyperhomocysteinemia, low folate status, homozygous C677T mutation of the methylene tetrahydrofolate reductase and renal arterial thrombosis.

We report a renal artery thrombosis in a 42-year-old man. Fasting homocysteinemia was at 23 micromol/l 3 months later and at 33 pmol/l 5 months after the vascular event. A homozygous C677T MTHFR was found with low folate status. Active smoking may also have contributed to the pathogenesis of renal arterial thrombosis. The other causes of thrombophilia were ruled out. Homocysteine lowering treament was started: homocysteine normalized at 10.6 micromol/l. There was no recurrence of vascular event within 18 months. We propose mild or moderate hyperhomocysteinemia triggered by low folate status in patients with homozygous C677T MTHFR as a cause of renal arterial thrombosis.