Abetalipoproteinemia (ABL) is an inherited condition that prevents the body from completely absorbing certain dietary fats. Without treatment, it can cause vitamin deficiencies that may have long term effects on your health. Dietary fats, and the vitamins they contain, are important for the growth and development of many of the bodies’ systems, including the brain.
ABL may also be called Bassen-Kornzweig syndrome, acanthocytosis, or apolipoprotein B deficiency. It is caused by a defective gene. Therefore, it runs in families. It is not contagious.
ABL is caused by problems with a gene that tells your body how to combine fat with protein to make something called a lipoprotein. When the gene doesn’t work, it is harder for your body to digest certain types of fat and vitamins.
ABL is a recessive condition. You must inherit the defective gene from both parents to be affected by the condition.
Symptoms of ABL vary greatly. This reflects the many important roles that fats and vitamins play in the body. Symptoms range from problems with growth and development in infancy to slurred speech and coordination issues in adults.
Specific symptoms of a ABL include:
- abnormal growth patterns in infants – developmental delays or “failure to thrive”
- curving of the spine
- problems with balance and dexterity
- problems with coordination
- muscle weakness
- protruding abdomen
- problems with vision
- speech disorders, slurring of speech
- fatty, frothy, foul-smelling, or otherwise irregular stools
If you have any of the symptoms of ABL, it is important to talk to your doctor. ABL is treatable, but treatment delays can have lasting effects.
Your doctor can use several different types of tests to diagnose ABL.
Blood Tests – Metabolic
One of the ways that doctors diagnose ABL is to look for changes in your metabolism. Tests for deficiencies in vitamins A, D, E, and K are common. Doctors may also test your levels of apolipoprotein B. Apolipoprotein B metabolism can be altered in people with ABL and other lipid disorders.
Your doctor may also run a complete blood count and a cholesterol study.
Blood Tests - Genetic
If you have a family history of ABL, your doctor may test you to see if you have mutations in your MTP gene. This is the gene responsible for causing ABL. Knowing whether you have the mutation is not only useful in figuring out if you’re affected by the condition. It can also help you decide whether your spouse needs to be tested before you have children.
Other Diagnostic Tests
In addition to testing your blood, your doctor may perform other exams to see how ABL is affecting your body. A few examples of such tests are:
- Eye exams to diagnose vision problems.
- Stool samples to see if your stool shows any of the classic signs of the condition.
- Electromyography to test your muscle activity and see if it has been affected by the condition.
It may take several visits to the doctor to diagnose ABL. It can sometimes be difficult to determine whether symptoms are caused by ABL or another condition.
ABL is usually treated with high doses of fat-soluble vitamins. You may also receive other supplements, including linoleic acid – an omega-6 fatty acid.
Diet can be an important part of treating ABL. Your doctor may recommend speaking to a nutritionist who can help you lower your fat intake. This might involve changing to skim milk or eating smaller servings of meat and other fatty foods
The specific complications of ABL vary from person to person, and prognosis depends on the extent of your illness. While many patients do well with treatment, ABL can cause serious problems with your muscles and nervous system.
There are several potentially severe complications of ABL. Visual problems may become worse over time and lead to blindness. Muscle function changes may produce tremors and lead to trouble walking or performing regular activities. Some people with ABL may also experience mental deterioration.
The good news is that treatments for these complications are available. Your doctors may not be able to restore perfect health; however, if you experience these symptoms, they can work with you to regain as much mental clarity, vision, and muscle function as possible.