Lecithin cholesterol acyltransferase deficiency
| Lecithin cholesterol acyltransferase deficiency | |
|---|---|
| Classification and external resources | |
| Specialty | endocrinology |
| ICD-10 | E78.6 |
| ICD-9-CM | 272.5 |
| OMIM | 245900 136120 |
| DiseasesDB | 7343 |
| eMedicine | med/1270 |
| MeSH | D007863 |
Lecithin cholesterol acyltransferase deficiency (LCAT deficiency) is a disorder of lipoprotein metabolism. The disease has two forms: Familial LCAT deficiency, in which there is complete LCAT deficiency, and Fish-eye disease, in which there is a partial deficiency.
Lecithin cholesterol acyltransferase catalyzes the formation of cholesterol esters in lipoproteins.
Both the familial type and Fish-eye disease are autosomal recessive disorders caused by mutations of the LCAT gene located on chromosome 16q22.1, which is the long (q) arm of chromosome 16 a position 22.1. Both diseases are very rare with ~70 reported cases of familial LCAT deficiency and ~30 cases of fish-eye disease.
Symptoms of the familial form include visual impairment caused by diffuse corneal opacities, target cell hemolytic anemia, and renal failure. Less common symptoms include atherosclerosis, hepatomegaly (enlarged liver), splenomegaly (enlarged spleen), and lymphadenopathy.
Fish-eye disease is less severe and most commonly presents with impaired vision due to corneal opacification. It rarely presents with other findings, although, atherosclerosis, hepatomegaly, splenomegaly, and lymphadenopathy can occur. Carlson and Philipson found that the disease was named so because the cornea of the eye was so opaque or cloudy with dots of cholesterol that it resembled a boiled fish.
If an individual only carry one copy of the mutated gene, they typically do not show symptoms.
A deficiency of LCAT causes accumulation of unesterified cholesterol in certain body tissues. Cholesterol effluxes from cells as free cholesterol and is transported in HDL as esterified cholesterol. LCAT is the enzyme that esterifies the free cholesterol on HDL to cholesterol ester and allows the maturation of HDL. LCAT deficiency does not allow for HDL maturation resulting in its rapid catabolism of circulating apoA-1 and apoA-2. The remaining form of HDL resembles nascent HDL.
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