None — Spinocerebellar Ataxia (SCA3)
Ataxia is the name for a group of conditions causing problems with coordination and balance. More than 25 different forms are known. Spinocerebellar ataxia type 3 (SCA3) is caused by an inherited genetic defect that leads to progressive degeneration of the cerebellum, the area of the brain that controls coordination. It is also known as Machado-Joseph disease.
As the brain's nerve cells die, communication to/from the coordination center is disrupted. Initially, patients have trouble maintaining balance while walking and may have frequent falls. The gait problems can become so severe others may mistake the patient as being drunk. Eventually, the coordination problems spread to the hands and arms. Patients may also develop slurred or unusual speech, changes in eye movement, vision problems, tremor and uncontrolled muscle contractions.
SCA3 is one of the most common forms of inherited ataxia. Symptoms most commonly appear in people 30 to 60. It affects men and women equally. The genetic defect is passed directly from one generation to the next. A child of a parent with SCA3 has a 50 percent chance of inheriting the defective gene.
A "Smoking" Clue
There is no effective treatment for SCA3 and other forms of ataxia. The goal of intervention is to improve quality of life. Medications can sometimes ease specific symptoms. Patients may be offered physical and occupational therapy to improve movement and coordination. A cane, walker or wheelchair may be needed to reduce risk for falls. Assistive devices, like keyboards for writing and speech, may be used to improve communication.
Theresa Zesiewicz, M.D., Neurologist with the USF Ataxia Research Center, in Tampa, FL, has tested the smoking cessation drug, CHANTIX®(varenicline) for patients with SCA3 and some other types of spinocerebellar ataxia. The idea to test the drug came from the observation of a patient who reported his walking and balance improved while talking CHANTIX. So investigators performed a small double-blind study comparing the effects of CHANTIX in ataxia patients against a placebo.
The phase I study found patients who took CHANTIX had significantly better walking function and better balance. They even had an improvement in levels of depression. Functional MRI (fMRI) studies done at the beginning and end of the study also showed changes in the brains of ataxia patients who were taking CHANTIX.
Zesiewicz says much more research needs to be done before CHANTIX can be recommended as a treatment for SCA3 and some other forms of ataxia. Though the medication is currently available as a prescription stop smoking treatment, she doesn't yet recommend it for ataxia patients because there can be side effects. She hopes the FDA will eventually grant the drug orphan status for certain forms of ataxia. In the meantime, Zesiewicz says the findings open the doorway to other possible mechanisms of using the brain's nicotine reward system as a treatment for ataxia.
Research compiled and edited by Barbara J. Fister
AUDIENCE INQUIRY
For general information on Spinocerebellar Ataxia type 3 (SCA3 – Machado-Joseph Disease) or other forms of ataxia:
National Ataxia Foundation, http://www.ataxia.org
National Institute of Neurological Disorders and Stroke, http://www.ninds.nih.gov
We Move, http://www.wemove.org/ataxia/ata.html
WSOC
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