According to several of our sources, spinocerebellar ataxia
3 (SCA3) is often not included in the main differential diagnoses
for multiple sclerosis (MS). Likewise, it appears MS is often not included in the main differential diagnoses for SCA3.
However, both conditions can cause ataxia and other neurological symptoms.
The presence or absence of other neurologic or systemic problems can often help to differentiate between causes of ataxia.
Therefore, evaluation by an experienced neurologist
would be needed to make a correct diagnosis. Many physicians fail to pursue further diagnostic testing when a patient is labeled as having MS. But, there are several features that should prompt a physician to explore other disorders, including having a family history
of neurologic disease (such as SCA3).
Obtaining a second opinion may be useful.
There are no specific tests for making a diagnosis of MS. The diagnosis often relies on a complete neurological exam, medical history, and ruling out other conditions that might cause similar signs and symptoms.
A diagnosis of SCA3, on the other hand, is based on the use of molecular genetic testing
to detect a specific type of mutation
(CAG trinucleotide repeat expansion
) in a gene
. Genetic testing
for SCA3 detects 100% of people with SCA3.
Therefore, when SCA3 is suspected, genetic testing can confirm the diagnosis.
If the disease-causing mutation in a family is known, genetic testing may also be considered for at-risk, adult family members without symptoms.
People who are concerned about a possible diagnosis of SCA3 are encouraged to speak with an experienced neurologist and/or a genetics professional regarding their questions and concerns.
Last updated: 8/31/2016
Last updated: 12/6/2017
We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please
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