Abetalipoproteinemia

What is abetalipoproteinemia?

Abetalipoproteinemia (pronounced “a-ba-tah-lip-o-pro-te-ne-me-ah”) is a rare genetic disorder that affects your body’s ability to absorb fat and certain vitamins from food. If you have abetalipoproteinemia, your body can’t produce certain molecules called lipoproteins. Lipoproteins transport fats, cholesterol and fat-soluble vitamins throughout your body. A lack of lipoproteins can lead to a deficiency of fats and vitamins, like vitamins A, D, E and K. This deficiency can lead to numerous health issues, including:

• Fat malabsorption: This can lead to diarrhea, weight loss and malnutrition.
• Vitamin deficiencies: These can cause a variety of issues, including vision problems, nervous system problems and muscle weakness.
• Acanthocytosis: This is a condition in which your red blood cells become abnormally shaped like stars or spurs. It can lead to anemia, a condition in which your body doesn’t have enough healthy red blood cells.

Abetalipoproteinemia is a serious condition that can lead to significant health problems. While there’s no cure, treatment can help manage symptoms and prevent complications. Treatment typically includes a low-fat eating plan, vitamin supplements and certain therapies to treat specific symptoms.

What are the symptoms of abetalipoproteinemia?

Abetalipoproteinemia symptoms typically begin in infancy. After breastfeeding, your newborn may experience vomiting, diarrhea and fatty, foul-smelling poop (steatorrhea). After a time, you may notice your baby isn’t gaining weight and growing at the expected rate (growth faltering).

In adults, abetalipoproteinemia affects a variety of systems throughout your body as a result of vitamin deficiency. The first sign is often the loss of certain reflexes. Other symptoms may include:

• Muscle cramps, weakness and pain.
• Fatigue, shortness of breath or heart palpitations.
• An increase in the curve of your lower spine (lordosis) or upper spine (kyphoscoliosis).
• Difficulty coordinating how your muscles work, causing clumsy or awkward movements (ataxia).
• Trouble controlling your tongue or voice box, causing you to slur words (dysarthria).
• Vision issues, like eye misalignment (strabismus), uncontrollable eye movements (nystagmus) or trouble with night vision (retinitis pigmentosa).
• Low levels of healthy red blood cells in your body, leading to tiredness and weakness (anemia).
• Yellow skin or whites of your eyes (jaundice).
• Swollen abdomen.
• Gradual brain damage.

How do you get abetalipoproteinemia?

A genetic change in the MTTP gene causes abetalipoproteinemia. The MTTP gene tells your body how to create a protein called microsomal triglyceride transfer protein (MTP). Your body needs this protein to produce molecules called lipoproteins in your liver and intestines.

You need lipoproteins for the transfer of fats, cholesterol and fat-soluble vitamins from your intestines to your bloodstream. Your blood carries lipoproteins throughout your body so your tissues can absorb these essential nutrients.

Changes in the MTTP gene mean your body can’t produce enough MTP protein. Without enough MTP protein, your body can’t transport fat through the cells lining the intestine, which secondarily affects lipoprotein production to properly transport and absorb nutrients. This can lead to nutritional deficiencies, which result in the symptoms of abetalipoproteinemia.

Abetalipoproteinemia inheritance

Families pass on abetalipoproteinemia in an autosomal recessive pattern. Autosomal recessive means that both parents had a copy of the mutated gene and passed it on to their child. But the parents didn’t have symptoms of abetalipoproteinemia themselves.

How is abetalipoproteinemia diagnosed?

Your healthcare provider will make an abetalipoproteinemia diagnosis by performing a physical exam. They’ll ask you about your symptoms and medical history. You’ll also have various blood tests to check for the signs of the condition. These tests will look for fat (lipid) levels and lipoproteins in your plasma. Blood tests will also check for the form and structure of your red blood cells, liver function and fat-soluble vitamin levels. Fat-soluble vitamins include vitamins A, D, E and K.

Other tests you may need include:

• An eye exam.
• A neurological exam.
• An endoscopy.
• A liver ultrasound.
• A stool test, particularly to assess fat loss.

In addition, your healthcare provider may recommend genetic testing to look for signs of a genetic mutation in the MTTP gene.

How is abetalipoproteinemia treated?

Abetalipoproteinemia treatment focuses on your specific symptoms. You’ll likely work with a team of healthcare providers, including:

• Neurologists.
• Liver specialists (hepatologists). Eye specialists (ophthalmologists).
• Specialists in the study of fats (lipidologists).
• Cardiologists.
• Bone specialists.
• Gastroenterologists.
• Dietitians.

In infants, your provider may recommend an eating plan supplemented with high medium-chain triglycerides (MCTs) and specific vitamins to promote typical growth and development.

Treatment for adults includes a therapeutic eating plan involving foods low in long-chain saturated fatty acids (fats), which should help relieve your gastrointestinal symptoms. Examples include:

• Chicken, turkey and other lean meats.
• Fish.
• Dried beans, peas and lentils.
• Nonfat or low-fat milk, cottage cheese and yogurt.
• Fruits and vegetables.
• Whole-grain breads, pastas, cereals and rice.

Your provider will also recommend very high doses of fat-soluble vitamins (like vitamins A, E, D, K) to help prevent or improve many of your symptoms. For example, treatment with vitamin E and vitamin A may prevent or slow down neurological and retinal complications. Vitamin D supplementation can help relieve some of the symptoms associated with bone growth.

Care for neurological complications may include physical therapy, speech therapy or occupational therapy.

Can abetalipoproteinemia be prevented?

Abetalipoproteinemia is a genetic condition, so you can’t prevent it. If you’re pregnant or considering pregnancy, you may want to find out about your risk of passing on the condition through genetic counseling.

What is the prognosis for abetalipoproteinemia?

The outlook (prognosis) for abetalipoproteinemia varies depending on several factors, including:

• Age at diagnosis.
• When treatment begins.
• Type of MTTP mutation.

Early diagnosis and treatment with vitamin supplementation can prevent, delay or reduce complications and improve the prognosis, enabling some people to live into their 70s. Without treatment, the condition can lead to nutritional deficiencies that can lead to death by your 20s.

What can’t I eat with this condition?

If you have abetalipoproteinemia, you’ll want to restrict your fat intake. Total fat intake should be less than 15 to 20 grams per day for adults and less than 5 grams per day for children.

When should I see my healthcare provider?

If you or your child has symptoms of abetalipoproteinemia, you should see a healthcare provider. While the symptoms of the condition can mimic other disorders, your provider will be able to run tests to confirm a diagnosis and begin treatment.

What questions should I ask my healthcare provider?

If you have abetalipoproteinemia, you may have many questions for your healthcare provider. Some questions you may want to ask them include:

• What’s the severity of my abetalipoproteinemia?
• How will this condition affect me in the long term?
• What’s the recommended treatment plan for me?
• What specific vitamins and supplements do I need to take, and for how long?
• Are there any dietary changes I need to make?
• What are the potential complications of abetalipoproteinemia?
• What can I do to prevent these complications?
• Are there any support groups or resources available for people with abetalipoproteinemia?

A note from Cleveland Clinic

While abetalipoproteinemia can be a challenging condition, it’s important to remember that there are effective treatment strategies available. With careful management through a low-fat eating plan, vitamin supplementation and certain therapies, you can significantly improve your quality of life and prevent complications. Many people with abetalipoproteinemia lead full and productive lives. The key is working closely with your healthcare provider to develop a treatment plan that meets your specific needs. Don’t hesitate to ask questions and voice any concerns you may have throughout the process.