Hypobetalipoproteinemia

Overview
Hypobetalipoproteinemia is a rare genetic disorder causing abnormally low levels of LDL cholesterol. It is thought to be caused by mutated apolipoprotein B. The patient can have hypobetalipoproteinemia and simultaneously have high levels of HDL cholesterol. According to The Merck Manual, "no treatment is required."

Typically in hypobtalipoproteinemia, plasma cholesterol levels will be around 80-120 mg/dL, LDL cholesterol will be around 50-80 mg/dL, and longevity can be expected with good nutrition.

Notably, in people who do NOT have the genetic disorder hypobetalipoproteinemia, a low cholesterol level may be a marker for poor nutrition, wasting disease, cancer, hyperthyroidism, and liver disease.