Hypolipidemia

[GarryDrold]

Hypolipidemia is abnormally low levels of lipids in the blood (total cholesterol less than 120 mg/dL [3.1 mmol/L] or low-density lipoprotein (LDL) cholesterol less than 50 mg/dL [1.3 mmol/L]).

Low lipid levels may result from rare genetic abnormalities or other disorders.
People with these genetic abnormalities may have fatty stools, grow poorly, and have intellectual disability.
Some genetic abnormalities are treated with supplements of fats, vitamin E, and other fat-soluble vitamins (vitamins A, D, and K).

(See also Overview of Cholesterol and Lipid Disorders.)
A low level of lipids in the blood may be due to a

Primary cause (a genetic disorder)
Secondary cause (another disorder the person has)

Having a low lipid level rarely causes a problem, but it may indicate the presence of another disorder. For example, a low cholesterol level may indicate

An overactive thyroid gland (hyperthyroidism)
Anemia
Undernutrition
Cancer
Chronic infection such as hepatitis C
Impaired absorption of foods from the digestive tract (malabsorption)

Therefore, doctors may suggest further evaluation when the cholesterol is very low on blood testing. The cause, once identified, is treated.
A few rare hereditary disorders, such as abetalipoproteinemia and hypoalphalipoproteinemia, result in lipid levels low enough to have serious consequences. Some people with a mutation in the PCSK9 (proprotein convertase subtilisin/kexin type 9) gene also have low lipid levels, but there are no serious consequences and no treatment is necessary.