Hereditary ataxia is the form of ataxia caused by the genetic inheritance of mutated genes. There are more than 70 types of hereditary ataxias, including both autosomal recessive and autosomal dominant ataxias, and can affect all areas of the body. Each individual ataxia is categorized by its specific genetic mutation.
A general definition of hereditary ataxia is that it is a condition that causes gradual damage to the spinal cord and cerebellum. The mutated genes do not allow proper growth and development of the nervous system and brain. Over time, this leads to the damage responsible for ataxia symptoms.
Ataxia is a condition that leads to a loss of muscle control and physical coordination. It can affect all of the body including the arms, legs, mouth, and eyes. When these areas are affected, problems with basic functions can occur, such as talking, walking, and even swallowing. Hereditary ataxia has neurological symptoms that do not appear suddenly, but rather over many years. As the condition progresses, the symptoms that are experienced will be more severe, leading to paralysis and wheelchair dependency.
Hereditary ataxia is the result of mutations of some genes a person inherits from one or both parents. All of the types of hereditary ataxias fall into one of two groups. Autosomal recessive ataxia is when genetic mutations are passed from both parents. Autosomal dominant ataxia is when only one parent passes mutation.
Friedreich’s ataxia and ataxia-telangiectasia are two types of autosomal recessive ataxia. In cases of Friedreich’s ataxia, symptoms start anytime between the ages of five and 20. Ataxia-telangiectasia symptoms, on the other hand, begin during infancy or before the age of five.
Two type of autosomal dominant ataxia are spinocerebellar and episodic ataxias. Symptoms of spinocerebellar ataxia begin around 30 to 40 years of age. Episodic ataxia is more rare with symptoms that appear during the teen years, and there are time periods where no symptoms will occur.
Genetic testing will be done if ataxia is suspected in order to determine the type of ataxia based on the specific mutated gene. A lumbar puncture is usually performed to test cerebrospinal fluid. Magnetic resonance imaging (MRI) or computer topography (CT) scans may be done to check for brain abnormalities.
The treatment for hereditary ataxia is symptomatic care. Ataxia cannot be cured, but the symptoms that are experienced can be managed in order to avoid extreme discomfort. Several different types of doctors will work to help patients deal with symptoms including a neurologist, occupational therapist, and speech therapist.