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 Overview of Cholesterol and Lipid Disorders The body needs fats for growth and energy. It also uses them to synthesize hormones and other substances needed for the body’s activities. The body may deposit excess fat in blood vessels and... read more .)
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
Impaired absorption of foods from the digestive tract (malabsorption Overview of Malabsorption Malabsorption syndrome refers to a number of disorders in which nutrients from food are not absorbed properly in the small intestine. Certain disorders, infections, and surgical procedures can... read more )
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.
In abetalipoproteinemia (Bassen-Kornzweig syndrome), virtually no LDL cholesterol is present, and the body cannot make chylomicrons and very-low-density lipoproteins (VLDL). As a result, the absorption of fat and fat-soluble vitamins is greatly impaired.
Symptoms first develop during infancy. Growth is poor. Bowel movements contain excess fat (a condition called steatorrhea), which can make the stools oily, foul smelling, and more likely to float in water. The retina of the eye degenerates, causing blindness (this condition is similar to retinitis pigmentosa Retinitis Pigmentosa Retinitis pigmentosa is a rare, progressive degeneration of the retina (the transparent, light-sensitive structure at the back of the eye) that eventually causes moderate to severe vision loss... read more ). The central nervous system may be damaged, resulting in loss of coordination (ataxia) and intellectual disability.
The diagnosis is made with blood tests. A biopsy of the intestine is also done. Genetic testing is also done.
Although abetalipoproteinemia cannot be cured, taking massive doses of vitamin E may delay the development of or slow the damage to the central nervous system. Treatment also includes supplements of dietary fat and vitamins A, D, and K.
Chylomicron retention disease (Anderson disease)
In chylomicron retention disease, a hereditary disorder, the body cannot make chylomicrons. Affected infants tend to develop fat malabsorption, steatorrhea, and failure to thrive and may develop symptoms of central nervous system damage similar to those of abetalipoproteinemia.
Levels of lipids in the blood are measured. In infants whose levels are very low, especially ones that are normally elevated after a meal, a biopsy of the intestine is done. Treatment is supplements of dietary fats and vitamins A, D, E, and K.
In hypobetalipoproteinemia, the LDL cholesterol level is very low. Usually, there are no symptoms and no treatment is required. In the most severe form of hypobetalipoproteinemia, almost no LDL cholesterol is present, and people have symptoms similar to those of abetalipoproteinemia.
The diagnosis is made by measuring lipid levels in the blood. If family members have the disorder, the diagnosis is more likely. Treatment for the most severe form is similar to that of abetalipoproteinemia and includes vitamins A, E, D, and K and supplementation of fat in the diet.