What is the expected laboratory finding in a patient with abetalipoproteinemia?

In abetalipoproteinemia, the underlying issue is a genetic deficiency in the protein necessary for the formation of apolipoprotein B (Apo B), which is critical for the assembly and secretion of lipoproteins such as chylomicrons and very low-density lipoproteins (VLDL). As a result, the body is unable to properly process and transport fats, leading to significant malabsorption of dietary lipids, including fats and fat-soluble vitamins.

Consequently, patients with this condition exhibit very low levels of serum cholesterol due to the impaired production of lipoproteins that carry cholesterol in the bloodstream. The failure to form these lipoproteins essentially leads to a deficiency in circulating cholesterol, making low serum cholesterol a hallmark finding in abetalipoproteinemia.

In this context, while other lipid parameters may give different results, such as potential elevations in triglycerides due to trapping of fat in the intestines, the defining characteristic of abetalipoproteinemia is indeed the low serum cholesterol levels. Thus, this laboratory finding strongly correlates with the pathophysiology of the disorder.