Ataxia with Vitamin E Deficiency

Ataxia with vitamin E deficiency (AVED) is an inherited disorder that affects the body's ability to utilize vitamin E. This condition will lead to difficulty coordinating movements, clumsiness of the hands, loss of reflexes in legs and sensation in extremities, and blurred vision. Most affected individual start to experience problems with movement between the age of 4 and 18 years, which will worsen with age. In some cases, the cognitive ability of the affected individuals may decline. If untreated, affected individuals become wheelchair bound between ages of 11 and 50 years as a result of lack of muscle control and/or leg weakness. The life expectancy of individuals with AVED may be shortened. AVED can be treated with vitamin E supplementation, which can reverse some symptoms if treatment is initiated during the progress of the disease, or prevent symptoms altogether if initiated before symptoms appear. AVED is caused by pathogenic variants in the TTPA gene.

AVED is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant in the gene 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.

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

AVED is a rare condition. Estimates for how often it occured were only made for selected populations, ranging from 0.6 to 3.5 affected per 1,000,000 newborns. Evidence from research studies indicates that AVED occurs more often in the Mediterranean and North African populations.

Genetics Home Reference: Ataxia with vitamin E deficiency (http://ghr.nlm.nih.gov/)

OMIM [VITAMIN E, FAMILIAL ISOLATED DEFICIENCY OF; VED: 277460] (http://www.ncbi.nlm.nih.gov/omim)
Gene Reviews: Ataxia with Vitamin E Deficiency (http://www.ncbi.nlm.nih.gov/books/NBK1116/)

• Full gene sequencing