In a metabolic disease, abnormal activity, like cells or tissues diseases (Cushing's disease, diabetes, cardiovascular conditions, and jaundice) are not contagious, yet result from other contagious diseases, like hepatitis, that then lead to a metabolic disease like hepatitis.

Genetic diseases are produced by flawed genetic codes found in chromosomes, which are the genetic material of the body. The nucleus of cells have the structures that have chromosomes, and they cause different genetic diseases, such as Down Syndrome, cystic fibrosis, sickle cell anemia, and hemophilia. All of these specific types of genetically produced diseases are not contagious to other people, however, they can be passed down through generations of families. Some people in families will not exhibit the characteristics of the specific disease, but they will still carry and pass it down to their children who may exhibit its characteristics.