There has been a big step made forward, and DNA samples are now collected and analyzed, see below. I also added the pedigrees in the post below this one [publicly available] of some of Radio's siblings that were also affected by myositis.
A link to the new DNA research, started in autumn 2009: http://www.veterinary-neurologist.co.uk/
please let anyone know who has an affected dog, as this will be of benefit to the entire Vizsla community.
thank you, Andrea