Hypolipoproteinemia refers to unusually low levels of fats (lipids) in the blood. Low lipid levels may be caused by rare genetic conditions, or be a sign of another disorder such as overactive thyroid, anemia, undernutrition, cancer, chronic infection, or impaired absorption of foods from the digestive tract. Associated genetic disorders includes abetalipoproteinemia, familial hypobetalipoproteinemia, and chylomicron retention disease. Signs and symptoms in the the genetic or familial form of hypolipoproteinemia vary. In hypobetalipoproteinemia the low density lipoprotein (LDL) cholesterol levels are very low, yet people with this syndrome typically have no symptoms nor require treatment. Other forms result in absent or near absent LDL levels and can cause serious symptoms in infancy and early childhood. Treatment for hypoproteinemia varies depending on the underlying cause and signs and symptoms present in each individual.

Familial hypobetalipoproteinemia is usually caused by mutations in the APOB gene. In a few cases, it may be caused by mutations in other genes, or the cause may be unknown. It is inherited in an autosomal codominant manner. This means that a mutation in one copy of the APOB gene can cause the condition, but changes in both copies of the gene cause more severe symptoms.

Abetalipoproteinemia is caused by mutations in the MTTP gene and is inherited in an autosomal recessive manner.

Chylomicron retention disease is caused by mutations in the SAR1B gene and is inherited in an autosomal recessive manner.