Lecithin cholesterol acyltransferase deficiency (LCAT deficiency) is disorder of lipoprotein

Lipoprotein

A lipoprotein is a biochemical assembly that contains both proteins and lipids water-bound to the proteins. Many enzymes, transporters, structural proteins, antigens, adhesins, and toxins are lipoproteins...

 metabolism.

Lecithin cholesterol acyltransferase catalyzes the formation of cholesterol esters in lipoproteins.

Types

The disease

Disease

A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...

 has two forms:

• familial LCAT deficiency in which there is complete LCAT deficiency.
• fish eye disease in which there is a partial deficiency.

Both are autosomal recessive disorders caused by mutations of the LCAT gene

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 located on chromosome

Chromosome

A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

 16q22.

Presentation

A deficiency of LCAT causes accumulation of unesterified cholesterol in certain body tissues. Symptoms of the familial form include diffuse cornea

Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...

l opacities, target cell hemolytic anemia

Hemolytic anemia

Hemolytic anemia is a form of anemia due to hemolysis, the abnormal breakdown of red blood cells , either in the blood vessels or elsewhere in the human body . It has numerous possible causes, ranging from relatively harmless to life-threatening...

 and proteinuria

Proteinuria

Proteinuria means the presence of anexcess of serum proteins in the urine. The protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine , retrograde ejaculation, pneumaturia due to a fistula, or drugs such as pyridium.- Causes...

 with renal failure

Renal failure

Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...

. Fish eye disease only causes progressive corneal opacification.

Mortility and Morbidity

Renal failure is the major cause of morbidity and mortility in complete LCAT deficiency, while in partial deficiency(bird's eye disease) major cause for morbidity is visual impairement due to corneal opacities. These patients have low HDL Cholesterol but surprisingly premature atherosclerosis is not seen. However, There are some reported cases.

Signs and symptoms

In complete LCAT deficincy patients may present with Anemia, Corneal opacities,Hepatosplenomegaly, renal insufficiency while in partial deficiency (bird's eye disease) corneal opacities is the main finding with hepatosplenomegaly.

Diagnosis

Battery of tests are required such as CBC for anemia, kidney functions, urine for proteinurea, Lipid profile,these patients have very low HDL cholesterol and high triglyceride level,High free cholesterol and low cholesterol esters levels. However definitive diagnosis rest with LCAT gene analysis for mutation and functional activity.