“…Downey [1992] independently proposed that MS may be caused by a disturbance in heme biosynthesis, after appropriate environmental exposure (e.g., virus infection or heavy metal intoxication) of genetically susceptible individuals. A multidiciplinary approach is needed to investigate our hypothesis that the MS phenotype in a subgroup of patients [Kotze and Rooney, 1997;Reich et al, 1998] is related to iron deficiency during heme synthesis, causing CNS damage and/or triggering an immune response. Future studies may lead to a clearer definition of disease mechanisms, improved management of MS [Rudick et al, 1997] and ultimately, the development of novel therapy to treat this major cause of neurologic disability.…”