Spinocerebellar degeneration, or Friedreich's ataxia, is a genetic degenerative disorder. It damages the nerves that send messages from the spinal cord and brain to the rest of the body. Affected individuals have difficulty walking and speaking. The disease is progressive and can eventually lead to death.
Friedreich's ataxia is caused by a defective gene on chromosome 9. This gene, called frataxin, causes the body to make too many copies of a DNA sequence called GAA. The more the body repeats this DNA sequence, the earlier the patient begins to develop symptoms.
This genetic abnormality interferes with the production of a protein also called frataxin. The mitochondria is the part of the cell that produces energy for the body. In a healthy body, the protein frataxin helps form sulfur and iron clumps, which the mitochondria need in order to produce energy. People who have spinocerebellar degeneration don't have enough frataxin, so their cells can't produce the amount of energy the body needs to function normally.
The mitochondria are not using iron as they should, so excess iron builds up in the body. Iron reacts with oxygen to produce irregular and dangerous molecules called free radicals. These molecules destroy healthy cells in the muscles and nerves. These cells cannot be replaced after they have been destroyed.
Spinocerebellar degeneration usually affects children between the ages of 5 and 15, and is more common in people of European or Indo-European descent. Boys and girls are affected in equal proportion. It is an autosomal recessive disorder, which means that patients who develop the disease get the gene from both their mother and father.
The earliest symptom of Friedreich's ataxia is muscle weakness. Patients have trouble balancing and walking, and their lack of coordination gradually worsens. Other symptoms include hearing loss and vision changes, speech irregularities, scoliosis, foot disorders, diabetes, and heart disease leading to heart failure. Doctors diagnose spinocerebellar degeneration by performing a variety of tests, including genetic testing, muscle biopsies, X-rays, and electrophysiological tests.
As of early 2011. There was no cure or prevention for the disease as of early 2011. Patients may eventually require braces, wheelchairs, or other walking aids as the disease progresses, as well as treatment for diabetes or disease. cardiac. Couples who have a family history of spinocerebellar degeneration should consult a genetic counselor to assess their risk of passing the disorder to their offspring.