What is the primary cause of abetalipoproteinemia?

Abetalipoproteinemia is primarily caused by a genetic defect that impairs the transport of apolipoprotein B (specifically, apo-B100), which is essential for the assembly and secretion of lipoproteins containing triglycerides and cholesterol. This condition leads to an inability to form low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL), resulting in a deficiency of these lipoproteins in the bloodstream.

Due to this transport defect, individuals with abetalipoproteinemia exhibit low levels of cholesterol and triglycerides, as well as abnormalities in fat absorption. The accumulation of unabsorbed dietary fats and the absence of adequate lipoprotein synthesis are critical characteristics of the disorder. Understanding this mechanism is crucial for recognizing the implications of the condition on lipid metabolism and nutrition management.

The other options do not address the underlying genetic nature of abetalipoproteinemia and are instead related to different aspects of lipid metabolism or dietary intake, which do not directly cause this specific condition.