A silent crippler stalks millions of North Americans. It afflicts one person with tremors, makes another depressed or psychotic, and causes agonizing leg pains or paralysis in still another. It can mimic Alzheimer€s disease, multiple sclerosis, early Parkinson€s disease, diabetic neuropathy, or chronic fatigue syndrome. It can make men or women infertile or cause development disabilities in their children. The disorder is vitamin B12 deficiency. This isn€t a new or fad disease. You€ll find it listed in the textbooks of any first-year medical student. Yet it may be the most misdiagnosed disease and, when this occurs, the consequences can be tragic.