MT-TP and abetalipoproteinemia: Efficient assembly of apolipoprotein B (apoB) 100 with triglyceride and cholesterol into VLDL requires the activity of an ER-resident microsomal triglyceride transfer protein (MTTP), and loss-of-function mutations within the MTTP gene are the cause of human abetalipoproteinemia, an autosomal recessive disease characterized by the total absence of triglyceride-rich lipoproteins in the plasma [51].