Hepatic lipase deficiency (Hepatic lipase deficiency) - Gen LIPC.

Hepatic lipase deficiency is a disorder that affects the body's ability to break down lipids. Affected individuals have an increased triglycerides and cholesterol in the blood. These individuals also have an increased concentration of high density lipoprotein (HDL) and decrease in the concentration of low density lipoproteins (LDL).

Normally, high concentrations of HDL and low LDL have a protective effect against atherosclerosis and heart disease. However, some individuals with hepatic lipase deficiency, who have this imbalance in HDL and LDL, develop atherosclerosis and heart disease in mid-adulthood, while others do not. It is unknown whether people with hepatic lipase deficiency are at increased risk of developing atherosclerosis or heart disease compared to individuals in the general population. Similarly, it is not clear how increasing concentrations of triglycerides and cholesterol in the blood affect the risk of developing atherosclerosis and heart disease in people with hepatic lipase deficiency.

Hepatic lipase deficiency is due to mutations in the gene LIPC, located on the long arm of chromosome 15 (15q21-q23). This gene encodes hepatic lipase enzyme. This enzyme is encoded by the liver cells and is released into the bloodstream where it helps transform very low-density lipoprotein (VLDL) and intermediate density lipoproteins (IDLs) in LDL. The enzyme also helps in transporting HDLs transporting cholesterol and triglycerides from the blood into the liver where HDLs deposit these fats so that they can be redistributed to other tissues or removed from the body. Hepatic lipase helps maintain the balance of these carrier molecules of fat by regulating LDL formation and transport of HDLs. Normally, high concentrations of HDL and low LDL have a protective effect against coronary heart disease.

They have identified at least 10 mutations in the LIPC gene in people with hepatic lipase deficiency. These mutations inhibit the release of hepatic lipase liver or decrease the enzyme activity in the bloodstream. Consequently, IDL and VLDL are not transformed efficiently in LDL and HDL cholesterol and triglycerides remain in the bloodstream. However, it is unclear what effect this change in the levels of fat in people with deficient hepatic lipase, or why some people affected develop atherosclerosis and heart disease in adulthood, while others do not.

This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.

Tests in IVAMI: in IVAMI perform detection of mutations associated with deficiency of hepatic lipase by the complete PCR amplification of exons LIPC gene, and subsequent sequencing.

Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).