Genetic factors are clearly indicated as evidenced by dominant mutations in three different genes have been identified that account for the small number of cases of familial, early - onset AD. (sciencedaily.com)
All breeding stock should be tested for simple dominant mutations. (ashgi.org)
However, if an incomplete dominant mutation did cause a disease, the same breeding and testing advice should be followed as for a simple dominant test, as noted above. (ashgi.org)