Abetalipoproteinemia
What is Abetalipoproteinemia?
Abetalipoproteinemia is a rare genetic disorder that affects how your body processes fats. People with this condition cannot make a protein called apolipoprotein B, which is essential for transporting fats and fat-soluble vitamins through the bloodstream. Without this protein, your body struggles to absorb fats from food and move them where they need to go.
This condition causes extremely low cholesterol levels, often below 50 mg/dL for total cholesterol. While low cholesterol usually sounds like good news, levels this low can signal a serious problem. The disorder prevents your body from forming lipoproteins like LDL cholesterol and chylomicrons, which are needed to deliver nutrients to your cells.
Abetalipoproteinemia typically appears in infancy or early childhood. It affects fewer than 1 in 1 million people worldwide. Without proper treatment, the condition can lead to serious complications including vision problems, nervous system damage, and digestive issues. Early detection through blood testing makes a significant difference in managing this condition and preventing long-term complications.
Symptoms
- Chronic diarrhea and fatty, foul-smelling stools, especially in infants
- Failure to gain weight or grow properly during childhood
- Stomach pain and bloating after eating
- Vision problems, including difficulty seeing in dim light
- Muscle weakness and poor coordination
- Loss of deep tendon reflexes
- Numbness or tingling in hands and feet
- Difficulty walking or balance problems
- Intellectual delays in some cases
- Eye abnormalities including abnormal star-shaped red blood cells visible in the retina
Symptoms typically begin in the first few months of life with digestive problems. Neurological symptoms often develop gradually during childhood and adolescence if the condition remains untreated. Some symptoms may not become apparent until later in life, making early testing critical for at-risk individuals.
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Causes and risk factors
Abetalipoproteinemia is caused by mutations in the MTTP gene. This gene provides instructions for making a protein that helps assemble apolipoprotein B-containing lipoproteins. The condition follows an autosomal recessive inheritance pattern, meaning a child must inherit one mutated gene from each parent to develop the disorder. Parents who carry one copy of the mutation typically have normal cholesterol levels and no symptoms.
Risk factors include having parents who are blood relatives, which increases the chance of inheriting two copies of the mutated gene. Having a sibling with the condition also increases risk. There are no lifestyle or environmental factors that cause this condition, as it is entirely genetic. Genetic counseling can help families understand their risk and make informed decisions about testing.
How it's diagnosed
Abetalipoproteinemia is diagnosed through blood tests that reveal extremely low cholesterol levels. Total cholesterol is typically below 50 mg/dL, and LDL cholesterol is often below 20 mg/dL or completely absent. Testing also shows very low or absent apolipoprotein B levels and extremely low LDL particle numbers. These findings are distinctly abnormal and point to a problem with lipoprotein production rather than just healthy cholesterol levels.
Rite Aid offers testing for the key biomarkers needed to detect this condition, including total cholesterol, LDL cholesterol, LDL particle number, and apolipoprotein B. Additional tests may include examining blood cells under a microscope to look for abnormal star-shaped red blood cells called acanthocytes. Genetic testing can confirm the diagnosis by identifying mutations in the MTTP gene. A doctor may also order tests to check fat-soluble vitamin levels, which are typically very low in people with this condition.
Treatment options
- High-dose supplementation with fat-soluble vitamins A, D, E, and K throughout life
- Very low-fat diet, typically limiting fat to less than 15 grams per day
- Medium-chain triglyceride oil supplements, which can be absorbed without apolipoprotein B
- Essential fatty acid supplementation under medical supervision
- Regular monitoring of vitamin levels and neurological function
- Eye exams to detect and monitor retinal problems
- Physical therapy to maintain muscle strength and coordination
- Working with a registered dietitian experienced in fat malabsorption disorders
- Occupational therapy for daily living skills if neurological symptoms develop
- Regular follow-up with a metabolic specialist or geneticist
Concerned about Abetalipoproteinemia? Get tested at Rite Aid.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
With early diagnosis and proper treatment, many people with abetalipoproteinemia live into adulthood with good quality of life. Starting high-dose vitamin supplementation early, especially vitamin E, can prevent or slow neurological and vision problems. Without treatment, the condition can lead to severe complications that significantly reduce life expectancy and quality of life.
There is currently no cure for abetalipoproteinemia because it is caused by genetic mutations. Treatment focuses on managing symptoms and preventing complications through vitamin supplementation and dietary modifications. These interventions must continue throughout life. Gene therapy is being studied but is not yet available as a treatment option.
Abetalipoproteinemia causes extremely low cholesterol levels, typically below 50 mg/dL for total cholesterol and below 20 mg/dL for LDL cholesterol. These levels are much lower than what is seen with diet, medications, or other conditions. The disorder also causes fat malabsorption and vitamin deficiencies, which distinguish it from simple low cholesterol.
People with abetalipoproteinemia cannot properly absorb or transport dietary fats because they lack apolipoprotein B. When they eat fat, it accumulates in intestinal cells and causes digestive symptoms like diarrhea and stomach pain. A very low-fat diet reduces these symptoms and prevents fat buildup in the body.
Vitamin E is the most critical supplement because deficiency causes severe neurological damage. Vitamins A, D, and K are also essential and must be supplemented throughout life. These are all fat-soluble vitamins that cannot be absorbed properly without apolipoprotein B. Regular blood tests monitor vitamin levels to ensure supplementation is adequate.
Yes, blood tests showing extremely low total cholesterol and absent LDL cholesterol can detect abetalipoproteinemia in newborns. Testing may be done if an infant has chronic diarrhea, failure to thrive, or a family history of the condition. Early detection allows treatment to begin immediately, preventing many complications.
Yes, abetalipoproteinemia follows an autosomal recessive inheritance pattern. A child must inherit one mutated MTTP gene from each parent to develop the condition. Parents who carry one mutation are typically healthy and have normal cholesterol levels. Each child of two carriers has a 25% chance of inheriting the condition.
Red blood cells develop an abnormal star-shaped or spiky appearance called acanthocytosis. These cells are also called spur cells. The abnormal shape occurs because the cell membrane lacks certain lipids that would normally be transported by apolipoprotein B-containing lipoproteins. Examining blood cells under a microscope can help support the diagnosis.
No, people with abetalipoproteinemia should never take cholesterol-lowering medications like statins. Their cholesterol is already dangerously low, and lowering it further could cause serious harm. If you have been diagnosed with this condition, make sure all your healthcare providers know about it to avoid inappropriate prescriptions.
People with abetalipoproteinemia should have blood tests at least twice per year to monitor vitamin levels and overall health. Testing should include fat-soluble vitamins A, D, E, and K, as well as liver function and cholesterol levels. More frequent testing may be needed when adjusting supplement doses or if symptoms develop.