Hypobetalipoproteinemia is a disorder consisting of low levels of

LDL cholesterol Low-density lipoprotein (LDL) is one of the five major groups of lipoprotein that transport all fat molecules around the body in extracellular water. These groups, from least dense to most dense, are chylomicrons (aka ULDL by the overall densit ...

apolipoprotein B Apolipoprotein B (ApoB) is a protein that in humans is encoded by the gene. Function Apolipoprotein B is the primary apolipoprotein of chylomicrons, VLDL, Lp(a), IDL, and LDL particles (LDL—commonly known as "bad cholesterol" when in refer ...

, below the 5th percentile. The patient can have hypobetalipoproteinemia and simultaneously have high levels of

HDL cholesterol High-density lipoprotein (HDL) is one of the five major groups of lipoproteins. Lipoproteins are complex particles composed of multiple proteins which transport all fat molecules (lipids) around the body within the water outside cells. They are t ...

. Notably, in people who do not have the genetic disorder hypobetalipoproteinemia, a very low cholesterol level (less than 100 mg/dl) may be a marker for poor nutrition, wasting disease, cancer, hyperthyroidism, and liver disease. In 1997 a study showed that Japanese Centenarians had tenfold increase of hypobetalipoproteinemia compared with controls.

Causes

One form is thought to be caused by mutated

. Another form is associated with

microsomal triglyceride transfer protein Microsomal triglyceride transfer protein large subunit is a protein that in humans is encoded by the ''MTTP'' gene. MTP encodes the large subunit of the heterodimeric microsomal triglyceride transfer protein. Protein disulfide isomerase (PDI) comp ...

which causes

abetalipoproteinemia Abetalipoproteinemia (also known as: Bassen-Kornzweig syndrome, microsomal triglyceride transfer protein deficiency disease, MTP deficiency, and betalipoprotein deficiency syndrome) is a disorder that interferes with the normal absorption of fat ...

. A third form,

chylomicron retention disease Chylomicron retention disease is a disorder of fat absorption. It is associated with SAR1B. Mutations in SAR1B prevent the release of chylomicrons in the circulation which leads to nutritional and developmental problems. It is a rare autosomal re ...

(CRD), is associated with SARA2.

Diagnosis

Typically in hypobetalipoproteinemia, plasma cholesterol levels will be around 80–120 mg/dL, LDL cholesterol will be around 50–80 mg/dL.

Treatment

Early high doses of

vitamin E Vitamin E is a group of eight fat soluble compounds that include four tocopherols and four tocotrienols. Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitami ...

in infants and children has shown to be effective.

References

External links

Lipid metabolism disorders {{blood-disease-stub