As you are aware, the causative mutation for gPRA in Schapendoes dogs has been found. A direct mutation test has been established, which analyses the mutation directly in the gene which is homozygous in affected Schapendoes dogs.
Since October 1st 2008 the Ruhr-Universität-Bochum in Germany offers the direct gene diagnostics for gPRA. The diagnostic certainty is virtually 100%. For breeding purposes heterozygous individuals (carriers) can be distinguished reliably from normal (homozygous) genotypes and from affected animals (homozygous mutant).
The order form for the Molecular Genetic Diagnostics of gPRA can be found here: [PDF]
Use the links below to read more about gPRA in your own language: