What is Abetalipoproteinemia

TL;DR: Abetalipoproteinemia is a rare genetic disorder that prevents the body from properly absorbing dietary fats and fat-soluble vitamins, leading to severe nutritional deficiencies and neurological complications. It is caused by mutations in the MTTP gene, which disrupts the body’s ability to transport fat from the intestines into the bloodstream.

What exactly is Abetalipoproteinemia?

Abetalipoproteinemia is a rare, inherited metabolic disorder characterized by the inability of the body to produce lipoproteins containing apolipoprotein B. Because these lipoproteins are essential for transporting fats, cholesterol, and fat-soluble vitamins (A, D, E, and K) through the bloodstream, patients with Abetalipoproteinemia experience systemic issues. Without treatment, the condition can lead to significant developmental delays, vision loss, and neurological impairment.

Which body systems are affected by Abetalipoproteinemia?

The impact of Abetalipoproteinemia is widespread due to the body’s fundamental need for dietary fats. Key systems affected include:

• Digestive System: Difficulty absorbing fats leads to steatorrhea (fatty, foul-smelling stools) and failure to thrive in infancy.


• Nervous System: A profound deficiency in Vitamin E can cause ataxia (loss of muscle coordination) and peripheral neuropathy.


• Ocular System: Retinitis pigmentosa, a progressive degeneration of the retina, is a hallmark of untreated Abetalipoproteinemia.


• Hematological System: The shape of red blood cells is altered, often resulting in "acanthocytes" (thorny-shaped cells).

How common is Abetalipoproteinemia and who is affected?

Abetalipoproteinemia is extremely rare, with fewer than 100 cases reported in medical literature globally. It is an autosomal recessive condition, meaning an individual must inherit two copies of the mutated MTTP gene—one from each parent. Because it is so rare, it does not show a strong bias toward any specific geographic region or gender, though early diagnosis is critical to preventing permanent neurological damage.

What differentiates Abetalipoproteinemia from other conditions?

Unlike other fat malabsorption disorders, Abetalipoproteinemia is uniquely defined by the complete absence of low-density lipoproteins (LDL) and very-low-density lipoproteins (VLDL) in the blood. This specific biochemical signature distinguishes it from hypobetalipoproteinemia, where these levels are merely low rather than absent.

Next steps

• Consult a metabolic specialist or a gastroenterologist to discuss high-dose Vitamin E supplementation, which is the cornerstone of Abetalipoproteinemia management.


• Join our community of 19 patients at DiseaseMaps.org to connect with others navigating this rare diagnosis.


• Request a referral to a genetic counselor to understand the inheritance pattern and screening options for family members.

Medical disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment; always seek the advice of your physician regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Abetalipoproteinemia.


• Orphanet: Rare disease database, entry for Abetalipoproteinemia (ORPHA:10).


• Online Mendelian Inheritance in Man (OMIM): Entry #200100.