Ataxia with Vitamin E Deficiency
What Your Test Results Mean:
Carriers typically show no symptoms of AVED; however, carriers are at an increased risk of having a child with AVED. Risk for the current or future pregnancies is dependent on your partner’s carrier status. Carrier testing of your partner is recommended in addition to consultation with a genetic counselor.
Disease Explained:
Ataxia with vitamin E deficiency is an inherited disorder characterized by neurological problems, such as difficulty coordinating movements (ataxia) and speech, loss of reflexes in the legs, and a loss of sensation in the extremities. Individuals with AVED are unable to properly retain and use dietary vitamin E causing damage to the body’s cells, especially nerve cells in the brain and spinal cord. Most individuals with AVED begin to experience symptoms before adulthood and if untreated may require use of a wheelchair by adulthood. If treated early and consistently with vitamin E, symptoms of the disease can be avoided.
How the Genetics Works:
Ataxia with vitamin E deficiency is an autosomal recessive disorder caused by pathogenic variants in the TTPA gene. All individuals have two copies of the TTPA gene. Carriers of AVED have a variant in one copy of the TTPA gene while individuals with AVED have mutations in both copies of the TTPA gene, one inherited from each parent. Risk for two carriers to have a child with the disorder is 25%.