This page is designed to give you a general understanding of how inheirtance of known health issues occurs in dogs. For a more complete understanding go to http://www.canine-genetics.com/Mutation.htm.  We actually recommend reading the entire Canine Genetics Project series of articles by Dr. John Armstrong. Health Issues General PRA - Progressive Retinal Atrophy NCL - Neuronal Canine Ceroid Lopofuscinosis DASHaHOUND Guarantee Double Dapples