Abetalipoproteinemia is caused by defects of the gene encoding the 97 kDa subunit of a microsomal triglyceride transfer protein

Abetalipoproteinemia is an inherited disorder of lipoprotein metabolism. Affected individuals produce virtually no circulating apolipoprotein B-containing lipoproteins (chylomicrons, very low density lipoprotein, low density lipoprotein and lipoprotein (a)). Malabsorption of the antioxidant vitamin E occurs, leading to spinocerebellar and retinal degeneration. Biochemical and genetic studies show that abetalipoproteinemia is not a defect of lipid biosynthesis or of the apolipoprotein B gene. Instead a microsomal triglyceride transfer protein, which exists as a complex with protein disulphide isomerase in the endoplasmic reticulum, has been implicated. We have cloned and sequenced the human cDNA encoding microsomal triglyceride transfer protein