Gene : MTTP

What is abetalipoproteinaemia?

Abetalipoproteinaemia is a rare inherited disorder where certain fats such as cholesterol and fat-soluble vitamins cannot be metabolized by the body. This leads to progressive neurological deterioration, movement problems, eye issues and abnormal blood cells. Symptoms begin to appear within the first month of life. Because the affected infant cannot absorb and metabolize certain fats they fail to gain weight and do not grow at the expected rate. They often have diarrhea and fatty, foul-smelling stool. As they age, affected individuals have a progressively harder time controlling their movements, lose their coordination and their muscles weaken. They also develop a degenerating condition that affects the retina of the eyes that could lead to vision loss, called retinitis pigmentosa. Their blood cells also appear as abnormal star-shaped cells instead of round discs. Intellect is typically not affected but cases of intellectual disability have been reported with abetalipoproteinaemia. Affected individuals can live into adulthood, though life expectancy is reduced. There is no cure for abetalipoproteinaemia, but medical care and surveillance can help to improve some symptoms and overall condition of life. Abetalipoproteinaemia is caused by pathogenic mutations in the MTTP gene.

How is abetalipoproteinaemia inherited?

Abetalipoproteinaemia is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

What does it mean to be a carrier?

There are generally no signs or symptoms associated with being a carrier for abetalipoproteinaemia. However, the risk to have a child affected with abetalipoproteinaemia is increased. Testing of reproductive partners is recommended for carriers of abetalipoproteinaemia.

How common is abetalipoproteinaemia?

Abetalipoproteinaemia is a very rare condition. Only around 100 cases have been reported worldwide.

Family References and Resources
Clinician References
What is Analyzed?
  • Full gene sequencing
Affected Systems






Carrier Rates
Detection Rate
Carrier Frequency
Ashkenazi Jewish > 99% 1 in 131
General Population > 99% 1 in 500

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