"Dr. Gary Johnson at the Animal Molecular Genetics Laboratory and Dr.
Joan Coates at the Comparative Neurology Program of the University of
Missouri and Drs. Claire Wade and Kerstin Lindblad-Toh at the Broad
Institute of MIT/Harvard and their colleagues have identified a DNA
mutation that is a major risk factor for development of degenerative
myelopathy in dogs.

A DNA test is now available for use by veterinarians, breeders and pet
owners. This test is available through the OFA (Orthopedic Foundation
for Animals). The test clearly identifies dogs that are clear (have 2
normal copies of the gene), those who are carriers (have one normal copy
of the gene and one mutated copy of the gene), and those who are at much
higher risk for developing DM (have 2 mutated copies of the gene).
However, having two mutated copies of the gene does not necessarily
result in disease."

Cost is $65.

Full announcement:
http://www.caninegeneticdiseases.net/DM/ancmntDM.htm

OFA link:
https://secure.offa.org/Cart.html