Ataxia with vitamin E deficiency

Ataxia with vitamin E deficiency is a disorder that impairs the body's ability to use vitamin E. Vitamin E is an antioxidant that protects cells in the body from the damaging effects of unstable molecules called free radicals. Lack of vitamin E causes neurological problems, such as difficulty coordinating movements (ataxia) and speech (dysarthria), loss of reflexes in the legs (lower limb areflexia), and a loss of sensation in the extremities (peripheral neuropathy). A few people with this condition have developed an eye disorder called retinitis pigmentosa that causes vision loss. Most people who have ataxia with vitamin E deficiency start to experience problems with movement between the age of 4 years and 18 years. The movement problems tend to worsen with age.

Ataxia with vitamin E deficiency is a rare condition; however, its prevalence is unknown.

Mutations in the TTPA gene cause ataxia with vitamin E deficiency. The TTPA gene provides instructions for making the α-tocopherol transfer protein (αTTP), which is found in the liver and brain. This protein controls the distribution of vitamin E obtained from the diet (also called α-tocopherol) to cells and tissues throughout the body. Cells neutralize free radicals with the aid of vitamin E, which prevents damage to the cell. Mutations in the TTPA gene impair the activity of the αTTP protein, resulting in an inability to retain and use dietary vitamin E. This deficiency leads to accumulation of free radicals within cells. Nerve cells (neurons) in the brain and spinal cord (central nervous system) are particularly vulnerable to the damaging effects of free radicals and die off when they are deprived of vitamin E. Nerve cell damage can lead to problems with movement and other features of ataxia with vitamin E deficiency.

Read more about the TTPA gene.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.