Adverse Effect of Nitrous Oxide in a Child with 5,10-Methylenetetrahydrofolate Reductase Deficiency

Nitrous oxide irreversibly oxidizes the cobalt atom of vitamin B12, inhibiting the cobalamin-dependent enzyme methionine synthase, which has a key role in many biochemical reactions that involve the nervous system. This case report concerns the neurologic deterioration and death of a child anesthetized twice, over a short period, with nitrous oxide before an inherited deficiency in 5,10-methylenetetrahydrofolate reductase (MTHFR), which is critical in similar metabolic pathways, was diagnosed.