Dominant Genetic Diseases: Introduction. Dominant diseases are genetic diseases that only require a single copy of the gene to be damaged. This error need only be inherited from one parent in order to get the disease. The bad gene from one parent dominates the other parent's good gene.esearch the causes of these diseases that are similar to, or related to, Dominant Genetic Diseases: 1  Marfan's syndrome. 2  Hereditary nonpolyposis colorectal cancer. 3  Multiple exostoses. 4  Huntington's disease. 5  Neurofibromatosis. 6  more related diseases...».