This study will determine whether short term intravenous infusion of vitamins A and E in patients with abetalipoproteinemia can reverse disease symptoms in these patients. Abetalipoproteinemia is an inherited metabolic defect that prevents fat-soluble vitamins, such as A and E, from being absorbed from the intestines into the bloodstream and from being secreted by the liver. The deficiencies of vitamins A and E can result in severe vision impairment and a gait disorder. Treatment with megadoses of these vitamins, taken by mouth, may delay or arrest symptoms, but many continue to progress.