The condition that does NOT cause high triglycerides is abetalipoproteinemia. Take each in turn. A fructose-rich diet floods the liver with substrate for de novo lipogenesis and accelerates VLDL secretion, elevating plasma TG. In diabetes mellitus, deficient or ineffective insulin lowers lipoprotein lipase activity and increases hepatic VLDL synthesis, a classic cause of hypertriglyceridemia. Nephrotic syndrome, through hypoalbuminemia, stimulates compensatory hepatic lipoprotein production, raising cholesterol and triglycerides together. Abetalipoproteinemia is the opposite scenario: a loss-of-function mutation in microsomal triglyceride transfer protein (MTP) prevents lipidation and assembly of apoB-containing particles, so chylomicrons, VLDL and LDL essentially vanish from plasma. The result is markedly low — not high — triglycerides and cholesterol, with fat malabsorption, acanthocytosis and fat-soluble vitamin deficiency. Hence it is the exception.\[\boxed{\text{Abetalipoproteinemia (low TG)}}\]