Beta-lipoproteins are involved in the transport of fats, cholesterol and fat soluble vitamins in the bloodstream. As fats and vitamins are essential to the development of cells and tissues, beta-lipoproteins play an essential physiological role in the body. MTTP is involved in the production of beta-lipoproteins by catalyzing the transport of cholesteryl ester, phospholipid and triglyceride from phospholipid surfaces.
Mutations in the MTTP gene have been associated with abetalipoproteinemia, a rare disorder characterized by the malabsorption of fats and lipid soluble vitamins resulting in hypocholesterolemia and vitamin deficiency. Mutations can result in the absence of the MTP protein or in a short non-functional version of it.