Final answer:
VLCFA deficiency without ketones is due to a defect in the triacylglycerol transfer protein, resulting in the absence of chylomicrons, VLDL, or LDL. Ketones are produced during the B-oxidation of fatty acids and serve as an alternative energy source in low glucose conditions. Excess acetyl-CoA is diverted to create ketone bodies through ketogenesis, leading to ketosis.
Step-by-step explanation:
VLCFA deficiency without ketones is due to a defect in the triacylglycerol transfer protein, which prevents the loading of apo B with lipid. This leads to the absence of chylomicrons, VLDL, or LDL. Additionally, there is low or absence of HDL. Ketones are produced during the B-oxidation of fatty acids and can serve as an alternative energy source in times of low glucose levels. Excess acetyl-CoA from fatty acid oxidation is diverted to create ketone bodies through the process of ketogenesis. These excess ketone bodies can result in ketosis.