Friedreich's ataxia is an inherited muscular disorder that affects a patient's coordination. The National Institute of Neurological Disorders and Stroke (NINDS) states that 1 in 50,000 people in the United States are diagnosed with Friedreich's ataxia. The age of onset is between 5 and 15, and both men and women can have the disorder. Friedreich's ataxia is caused by an abnormal gene, which affects normal communication in the cerebellum, spinal cord and peripheral nerves. Parts of the brain that affect thinking or memory are not affected by Friedreich's ataxia.
Neurons
Neurons are essential in the construction of the brain. Each neuron is made up of three parts: soma, axon and dendrites; the soma is the cell body, which is connected to a long axon that sends the signal out via the dendrites. The Better Health Channel states that the axon is damaged in Friedreich's ataxia; in particular, the abnormal gene results in faulty formation of the myelin sheath, which wraps around the axon and protects it. Without the myelin, the communication between the neurons breaks down, interfering in normal brain function. The affected neurons in Friedreich's ataxia are motor neurons, located in the cerebellum and the spinal cord.
Cerebellum
The cerebellum is the coordination center of the brain, located near the base of the head. The Better Health Center notes that the cerebellum also controls movement in the head, eyes and neck. Damage to the cerebellum results in symptoms such as a lack of balance and physical coordination, and jerky movements in the leg. As the neurons continue to deteriorate in the cerebellum, the patient requires a wheelchair to move.
Spinal Cord and Peripheral Nerves
While not in the brain, the spinal cord and peripheral nerves are also affected by Friedreich's ataxia. The brain and spinal cord are both part of the central nervous system, while the peripheral nervous system is a separate system of nerves. The spinal cord controls the voluntary movement of the skeletal muscles, which is disrupted by the disorder. Sensation problems that arise in the disorder are caused by damage to the sensory nerves in the peripheral nervous system.
