Vitamin Replacement in Abetalipoproteinemia

Fat-soluble vitamins are normally absorbed from the diet through the gastrointestinal tract and incorporated into fat-rich particles called chylomicrons made in the intestinal wall. Chylomicrons are secreted by the intestine into the bloodstream. In a rare lipid metabolic disorder called abetalipoproteinemia, a defect in the assembly of the fat and vitamin containing particles prevents the formation of chylomicrons resulting in the malabsorption of fat and fat-soluble vitamins. A similar assembly defect of fat and fat-soluble vitamins occurs in the liver and prevents the secretion of these particles. Severe fat-soluble vitamin deficiency results even despite mega doses of oral fat-soluble vitamins. Clinically, the subjects develop neurologic and ophthalmologic symptoms similar to those in Vitamin A and E deficiency. This study is designed to determine whether short-term intravenous fat-soluble vitamins and fat emulsion can reverse the neurologic and ophthalmologic complications of fat-soluble vitamin deficiency based on noninvasive procedures routinely employed in clinical practice.