Complete LCAT deficiency - Genetics Home Reference
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Complete LCAT deficiency
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Reviewed August 2013
What is complete LCAT deficiency?
Complete LCAT deficiency is a disorder that primarily affects the eyes and kidneys.
In complete LCAT deficiency, the clear front surface of the eyes (the corneas) gradually becomes cloudy. The cloudiness, which generally first appears in early childhood, consists of small grayish dots of cholesterol (opacities) distributed across the corneas. Cholesterol is a waxy, fat-like substance that is produced in the body and obtained from foods that come from animals; it aids in many functions of the body but can become harmful in excessive amounts. As complete LCAT deficiency progresses, the corneal cloudiness worsens and can lead to severely impaired vision.
People with complete LCAT deficiency often have kidney disease that begins in adolescence or early adulthood. The kidney problems get worse over time and may eventually lead to kidney failure. Individuals with this disorder also usually have a condition known as hemolytic anemia, in which red blood cells are broken down (undergo hemolysis) prematurely, resulting in a shortage of red blood cells (anemia). Anemia can cause pale skin, weakness, fatigue, and more serious complications.
Other features of complete LCAT deficiency that occur in some affected individuals include enlargement of the liver (hepatomegaly), spleen (splenomegaly), or lymph nodes (lymphadenopathy) or an accumulation of fatty deposits on the artery walls (atherosclerosis).
In complete LCAT deficiency, the clear front surface of the eyes (the corneas) gradually becomes cloudy. The cloudiness, which generally first appears in early childhood, consists of small grayish dots of cholesterol (opacities) distributed across the corneas. Cholesterol is a waxy, fat-like substance that is produced in the body and obtained from foods that come from animals; it aids in many functions of the body but can become harmful in excessive amounts. As complete LCAT deficiency progresses, the corneal cloudiness worsens and can lead to severely impaired vision.
People with complete LCAT deficiency often have kidney disease that begins in adolescence or early adulthood. The kidney problems get worse over time and may eventually lead to kidney failure. Individuals with this disorder also usually have a condition known as hemolytic anemia, in which red blood cells are broken down (undergo hemolysis) prematurely, resulting in a shortage of red blood cells (anemia). Anemia can cause pale skin, weakness, fatigue, and more serious complications.
Other features of complete LCAT deficiency that occur in some affected individuals include enlargement of the liver (hepatomegaly), spleen (splenomegaly), or lymph nodes (lymphadenopathy) or an accumulation of fatty deposits on the artery walls (atherosclerosis).
How common is complete LCAT deficiency?
Complete LCAT deficiency is a rare disorder. Approximately 70 cases have been reported in the medical literature.
What genes are related to complete LCAT deficiency?
Complete LCAT deficiency is caused by mutations in the LCAT gene. This gene provides instructions for making an enzyme called lecithin-cholesterol acyltransferase (LCAT).
The LCAT enzyme plays a role in removing cholesterol from the blood and tissues by helping it attach to molecules called lipoproteins, which carry it to the liver. Once in the liver, the cholesterol is redistributed to other tissues or removed from the body. The enzyme has two major functions, called alpha- and beta-LCAT activity. Alpha-LCAT activity helps attach cholesterol to a lipoprotein called high-density lipoprotein (HDL). Beta-LCAT activity helps attach cholesterol to other lipoproteins called very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL).
LCAT gene mutations that cause complete LCAT deficiency either prevent the production of LCAT or impair both alpha-LCAT and beta-LCAT activity, reducing the enzyme's ability to attach cholesterol to lipoproteins. Impairment of this mechanism for reducing cholesterol in the body leads to cholesterol deposits in the corneas, kidneys, and other tissues and organs. LCAT gene mutations that affect only alpha-LCAT activity cause a related disorder called fish-eye disease that affects only the corneas.
Read more about the LCAT gene.
Read more about fish-eye disease.
The LCAT enzyme plays a role in removing cholesterol from the blood and tissues by helping it attach to molecules called lipoproteins, which carry it to the liver. Once in the liver, the cholesterol is redistributed to other tissues or removed from the body. The enzyme has two major functions, called alpha- and beta-LCAT activity. Alpha-LCAT activity helps attach cholesterol to a lipoprotein called high-density lipoprotein (HDL). Beta-LCAT activity helps attach cholesterol to other lipoproteins called very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL).
LCAT gene mutations that cause complete LCAT deficiency either prevent the production of LCAT or impair both alpha-LCAT and beta-LCAT activity, reducing the enzyme's ability to attach cholesterol to lipoproteins. Impairment of this mechanism for reducing cholesterol in the body leads to cholesterol deposits in the corneas, kidneys, and other tissues and organs. LCAT gene mutations that affect only alpha-LCAT activity cause a related disorder called fish-eye disease that affects only the corneas.
Read more about the LCAT gene.
Read more about fish-eye disease.
How do people inherit complete LCAT deficiency?
This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
Where can I find information about diagnosis or management of complete LCAT deficiency?
These resources address the diagnosis or management of complete LCAT deficiency and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
- Genetic Testing Registry: Norum
disease - MedlinePlus Encyclopedia: Corneal
Transplant - National Heart, Lung, and Blood Institute: How is Hemolytic Anemia
Treated? - National Institutes of Diabetes and Digestive and Kidney Diseases: Kidney Failure -- Choosing a Treatment That's Right for
You - Oregon Health and Science University: Corneal
Dystrophy - The Foundation of the American Academy of Ophthalmology: Corneal
Transplants
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about complete LCAT deficiency?
You may find the following resources about complete LCAT deficiency helpful. These materials are written for the general public.
- MedlinePlus - Health information (4 links)
- Genetic and Rare Diseases Information
Center - Information about genetic conditions and rare diseases - Additional NIH Resources - National Institutes of Health (3 links)
- Educational resources - Information pages (2 links)
- Patient support - For patients and families (4 links)
- Genetic Testing Registry - Repository of genetic test information (1 link)
ClinicalTrials.gov - Linking patients to medical researchPubMed - Recent literatureOMIM - Genetic disorder catalog
What other names do people use for complete LCAT deficiency?
- familial LCAT deficiency
- familial lecithin-cholesterol acyltransferase deficiency
- FLD
- LCAT deficiency
- lecithin acyltransferase deficiency
- lecithin:cholesterol acyltransferase deficiency
- Norum disease
- Norum's disease
For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines and How are genetic conditions and genes named? in the Handbook.
What if I still have specific questions about complete LCAT deficiency?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
- What does it mean if a disorder seems to run in my family?
- What are the different ways in which a genetic condition can be inherited?
- If a genetic disorder runs in my family, what are the chances that my children will have the condition?
- Why are some genetic conditions more common in particular ethnic groups?
What glossary definitions help with understanding complete LCAT deficiency?
anemia ; artery ; atherosclerosis ; autosomal ; autosomal recessive ; cell ; cholesterol ; deficiency ; enzyme ; familial ; gene ; HDL ; hemolysis ; hemolytic anemia ; kidney ; LDL ; lipoprotein ; lymph ; recessive ; splenomegaly ; VLDL
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (5 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.
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