Familial Hypobetalipoproteinemia
What is Familial Hypobetalipoproteinemia?
Familial hypobetalipoproteinemia is a rare genetic condition that causes very low levels of cholesterol in your blood. It happens when your body has trouble making or releasing a protein called apolipoprotein B, or Apo B. This protein is needed to transport cholesterol and fats through your bloodstream.
Most people with this condition inherit one altered gene from a parent. This is called heterozygous familial hypobetalipoproteinemia. These people usually have very low LDL cholesterol, often below the 5th percentile for their age. Many feel healthy and have no symptoms. A smaller number of people inherit two altered genes, one from each parent. This homozygous form is much more severe and causes serious problems with absorbing fats and fat-soluble vitamins from food.
While low cholesterol is usually considered healthy, extremely low levels from this genetic condition can sometimes lead to nutrient deficiencies. Understanding whether your low cholesterol is genetic helps your doctor monitor your health and prevent complications.
Symptoms
- Very low LDL cholesterol levels, often below 50 mg/dL
- Difficulty absorbing fats from food, mainly in severe cases
- Fatty or greasy stools that float
- Diarrhea or loose bowel movements
- Abdominal pain or bloating after eating fatty foods
- Vitamin A, D, E, and K deficiencies in severe cases
- Vision problems from vitamin A deficiency
- Weak bones from vitamin D deficiency
- Bleeding issues from vitamin K deficiency
- Nerve problems from vitamin E deficiency
Many people with the mild form have no symptoms at all. Low cholesterol is often discovered during routine blood testing. The severe form usually causes symptoms in childhood.
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Causes and risk factors
Familial hypobetalipoproteinemia is caused by mutations in genes that control how your body makes apolipoprotein B. The most common gene affected is the APOB gene itself. These mutations reduce the amount of Apo B protein your body produces or interfere with how it works. Without enough working Apo B, your liver cannot properly package and release cholesterol into your bloodstream.
This condition is inherited, meaning it passes from parents to children through genes. If you inherit one mutated gene, you develop the mild form with very low cholesterol but usually few problems. If you inherit two mutated genes, you develop the severe form with serious fat absorption issues. People with a family history of extremely low cholesterol should consider genetic testing and monitoring.
How it's diagnosed
Familial hypobetalipoproteinemia is diagnosed through blood tests that measure specific cholesterol markers. The key tests include Apolipoprotein B, which is typically below the 5th percentile in affected people, and LDL Particle Number, which is also very low. Standard cholesterol panels will show extremely low LDL cholesterol levels. These blood tests help distinguish this genetic condition from other causes of low cholesterol, like malnutrition or liver disease.
Rite Aid offers testing for Apolipoprotein B and LDL Particle Number as add-ons to our flagship panel. These tests can help identify unusually low levels that may indicate this condition. If your results suggest familial hypobetalipoproteinemia, your doctor may recommend genetic testing to confirm the diagnosis and determine which form you have.
Treatment options
- Monitor fat-soluble vitamin levels regularly through blood tests
- Take vitamin A, D, E, and K supplements if levels are low
- Eat a balanced diet with adequate healthy fats
- Reduce fat intake only if severe symptoms occur
- Use medium-chain triglyceride oil, which is easier to absorb
- Work with a dietitian to ensure proper nutrition
- Get regular eye exams to check for vitamin A deficiency
- Monitor bone health with vitamin D and calcium
- Check liver function periodically
- Screen family members who may have inherited the condition
Need testing for Familial Hypobetalipoproteinemia? Add it to your panel.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
Familial hypobetalipoproteinemia is a genetic condition that causes very low cholesterol levels in your blood. It happens when mutations affect how your body makes or releases apolipoprotein B, a protein needed to transport cholesterol. Most people inherit one altered gene and have mild symptoms, while those who inherit two altered genes can have severe fat absorption problems.
Many people with the mild form have no symptoms and only discover low cholesterol during routine testing. The severe form can cause fatty stools, diarrhea, abdominal pain, and deficiencies in vitamins A, D, E, and K. These vitamin deficiencies can lead to vision problems, weak bones, bleeding issues, and nerve damage if left untreated.
Diagnosis involves blood tests measuring Apolipoprotein B and LDL Particle Number, both of which are very low in this condition. Apo B levels are typically below the 5th percentile. Genetic testing can confirm the diagnosis and identify which gene mutation is responsible. These tests help distinguish this inherited condition from other causes of low cholesterol.
The mild form is usually not dangerous and many people live normal, healthy lives. The severe form can cause serious problems if not managed properly, including malnutrition and vitamin deficiencies. With proper monitoring and vitamin supplementation when needed, most complications can be prevented. Regular blood tests help catch any issues early.
There is no cure, but the condition can be managed effectively. Treatment focuses on monitoring vitamin levels and supplementing vitamins A, D, E, and K when needed. People with severe forms may need to adjust their diet and use special fats that are easier to absorb. Regular follow-up with your doctor helps prevent complications.
The key blood tests are Apolipoprotein B and LDL Particle Number, both of which are extremely low in this condition. A standard lipid panel will also show very low LDL cholesterol levels. These tests help identify the condition and monitor your levels over time to ensure you are not developing nutrient deficiencies.
Yes, this condition is inherited through genes passed from parents to children. If you inherit one mutated gene, you develop the mild form with very low cholesterol. If you inherit two mutated genes, one from each parent, you develop the severe form. Family members of affected individuals should consider screening.
Most people with the mild form do not need major diet changes and should eat a balanced, healthy diet. Those with the severe form may need to limit fat intake or use medium-chain triglyceride oil, which is easier to absorb. Working with a dietitian can help ensure you get proper nutrition while managing symptoms.
You should monitor fat-soluble vitamins A, D, E, and K through regular blood tests. These vitamins need fat to be absorbed properly, and people with this condition can develop deficiencies. Your doctor may recommend supplements if your levels are low. Monitoring helps prevent complications like vision problems, weak bones, and nerve damage.
Yes, children can inherit this condition from their parents. The severe form usually causes symptoms in childhood, including growth problems and vitamin deficiencies. The mild form may not be discovered until routine cholesterol testing later in life. If one parent has the condition, children have a 50 percent chance of inheriting it.