Ataxia is a group of progressive neurological diseases which affects coordination and speech. An estimated 150,000 Americans are affected by heredity or sporadic ataxia. Ataxia can strike anyone at any time regardless of age, gender, or race. The word "ataxia" means "absence or loss of order". Ataxia does not refer to a specific disease or disorder. Rather, it is a set of symptoms caused by a dysfunction in the the parts of the nervous system that coordinate movement, such as the cerebellum and the connections that transfer information to and from the cerebellum. People who have ataxia have uncontrolled, uncoordinated movements in the way they walk, move their arms or eyes, or talk. Ataxia can have many different underlying causes.

Regardless of cause, Ataxia affects every person differently. Even for inherited ataxias, the condition may affect many family members with the same type of inherited ataxia, but they may all have unique symptoms and/or severities.


Spinocerebellar ataxia (SCA) is a progressive, neurodegenerative, genetic disease with multiple types, each of which could be considered a disease in its own right.

All types of SCA are characterized by a progressive incoordination of walking. In addition, they are often associated with poor coordination of hand movements, eye movements, and speech. With some exceptions, the onset of symptoms usually occurs after the age of 18 ("adult-onset"). SCA is slowly progressive, which means that symptoms of the condition gradually worsen over a period of years. Some types of SCA can progress more rapidly than others.

SCAs are the largest group of the hereditary ataxias. It is caused by an autosomal dominant pattern of inheritance which means that only one copy of the defective gene is needed to inherit the disease. Both male and female individuals are equally likely to inherit the gene and develop the disease. It passes directly from one generation to the next without skipping. Individuals who escape the disease will not pass it on to future generations. People with a defective gene have a 50% chance of passing it on to each of their children.

There have been up to 36 different types of SCAs identified (see the list here). The spinocerebellar ataxias are labeled using the acronym "SCA" and then numbered in the order of their discovery.

At this time, there is no cure or treatment that can prevent or slow the progression of symptoms or the damage to the cerebellum.

Resources: Ataxia Center @ University of Minnesota, "Spinocerebellar Ataxia: Making an Informed Choice About Genetic Testing" booklet by University of Washingtom, National Ataxia Foundation, wikipedia.org