This paper examines hypolipoproteinemia, a condition characterized by abnormally low levels of lipids in the blood. It discusses the genetic and secondary causes of the disorder, including overactive thyroid, anemia, and malabsorption, as well as associated conditions such as abetalipoproteinemia and familial hypobetalipoproteinemia. The paper explains the clinical features of impaired fat transport, the biochemistry of the Lp(a) plasma lipoprotein, and the role of the kidney and liver in regulating Lp(a) concentration. Finally, it reviews current therapeutic strategies—aspirin, niacin, and hormone replacement therapy—along with emerging agents such as Tibolone and Tamoxifen, while noting gaps in clinical research.
One of the diseases of lipoprotein metabolism is hypolipoproteinemia. It is a condition that occurs when there are abnormally low levels of lipids or fats in the blood. Such low levels of fats can be caused by genetic disorders or by other conditions such as an overactive thyroid, undernutrition, certain chronic infections, anemia, cancer, and reduced absorption of nutrients from the digestive tract.1 These genetic abnormalities can give rise to related conditions including chylomicron retention disease, familial hypobetalipoproteinemia, and abetalipoproteinemia. In some cases, even individuals with low LDL cholesterol levels show no symptoms or signs of illness. When such conditions manifest during infancy or early childhood, serious treatment may be required.
The clinical features of hypolipoproteinemia involve low blood fat levels that cause severe metabolic abnormalities. The normal process by which blood absorbs dietary fats and transports them to where they are needed in the body is disrupted.2 As a result, proteins and other nutrients do not reach the appropriate tissues; instead, fats are sent directly to the liver for further processing, producing cholesterol that is treated as a waste product. Proteins are responsible for conveying other chemicals around the body, and this transport function is also impaired when lipoprotein levels are abnormally low.
Hypolipoproteinemia is associated with low plasma levels of the lipoprotein Lp(a). A threshold value of Lp(a) greater than 30 mg/dL is used to define hypolipoproteinemia in clinical practice.3 This plasma lipoprotein is rich in cholesterol and relatively low in protein. The Lp(a) molecule is bonded at a specific molecular weight, forming the apolipoprotein Apo(a), and its exclusive synthesis in the liver is encoded by the Lp(a) gene. Structurally, Lp(a) is homologous with plasminogen.
Genetically determined factors cause Lp(a) concentrations to vary across bloodstreams, genders, and ethnicities. Fewer Apo(a) kringle-IV repeat units are associated with higher plasma Lp(a) levels. Additionally, the rate of Lp(a) production by hepatocytes is a major determinant of plasma Lp(a) regulation. The kidney plays a key role in Lp(a) regulation, and the mass production of cholesterol associated with elevated Lp(a) contributes to increased cardiovascular disease risk through the distinctive physiological role of this lipoprotein.
The primary therapeutic strategies for managing hypolipoproteinemia include aspirin, niacin, and estrogen or hormone replacement therapy.3 Aspirin is thought to ameliorate aspects of hypolipoproteinemia through its anti-platelet and anti-inflammatory activities. Patients with elevated Lp(a) who are at risk of developing cardiovascular disease are advised to use aspirin to reduce cardiovascular incidents and improve cholesterol control.
"Aspirin, niacin, and hormone replacement therapy options"
"Tibolone, Tamoxifen, and unresolved clinical questions"
"Cited sources for disease and treatment data"
Always verify citation format against your institution’s current style guide requirements.