While the team at the Brotman-Baty Starita lab is not doing any genetic testing research on patient samples at this time, there are existing options for obtaining a clear diagnosis for CADASIL.
For doctors, talk to your lab or institution and inform them that you need to send genetic testing for diagnosis/prognosis/management. The hospital may allow you to send genetic testing through the hospital like you would any other lab.
Affected family members may visit with their neurologist to discuss testing, and request that it be covered by insurance.
There are a number of labs that will do the testing. Prevention Genetics, in particular, is known for Notch3 (CADASIL) testing.