Friedreich's Ataxia is a genetic, progressive, neurologic movement disorder that typically becomes apparent before adolescence. Initial symptoms may include unsteady posture, frequent falling, and progressive difficulties walking due to an impaired ability to coordinate voluntary movements (ataxia). Affected individuals may also develop abnormalities of certain reflexes; characteristic foot deformities; increasing incoordination of the arms and hands; slurred speech (dysarthria); and rapid, involuntary eye movements (nystagmus). Friedreich's Ataxia may also be associated with cardiomyopathy, a disease of cardiac muscle that may be characterized by shortness of breath upon exertion (dyspnea), chest pain, and irregularities in heart rhythm (cardiac arrythmias). Some affected individuals may also develop diabetes mellitus, a condition in which there is insufficient secretion of the hormone insulin. Primary symptoms may include abnormally increased thirst and urination (polydipsia and polyuria), weight loss, lack of appetite, fatigue, and blurred vision.
Friedreich's Ataxia may be inherited as an autosomal recessive trait. Cases in which a family history of the disease has not been found may represent new genetic changes (mutations) that occur spontaneously (sporadically). Friedreich's Ataxia results from mutations of a gene known as "X25" or "frataxin" located on the long arm (q) of chromosome 9 (9q13). In most affected individuals, the frataxin gene contains errors in the coded "building blocks" (nucleotide bases) that make up the gene's instructions. The symptoms and findings associated with Friedreich's Ataxia are thought to result primarily from degenerative changes of nerve fibers of the spinal cord as well as peripheral nerves, which are the motor and sensory nerves and groups of nerve cell bodies (ganglia) outside the brain and spinal cord.
