How is CSNB inherited?
In the Appaloosa, all the evidence we have gathered points to LP itself, the main Appaloosa gene, being the cause of CSNB. There is a small chance that the causative mutation for CSNB is not within LP itself, but in a very closely linked gene that lies next to LP on horse chromosome 1. Until we know what the causative mutation is for LP and have tested many night blind horses we won’t know for sure. However, statistical probability of the ERG testing combined with the preliminary expressional analysis of our candidate gene for LP suggests that LP itself is the cause of CSNB. Even if it is not, a tightly linked gene containing the CSNB mutation will very seldom separate from LP during recombination. This will happen so that LP and the cause of CSNB would be inherited together almost all the time (over 90%), meaning that effectively, they are being inherited as a single unit. So, to track the inheritance of the disease, LP would work as a reliable indicator, even if it proves not to be t
