The Medical Genetics science is concerned with the study of genetic diseases that affect humans, with a focus on clinical applications, and the mutations and their various effects on human health. It is the science of studying the genetic mechanisms related to the transition from the normal composition to pathological cases, and how genes and environment can interact to affect the incidence of the diseases to humans. This science is also concerned with the study of the basic principles of classical genetics science and the molecular genetics. Moreover, the Medical Genetics science is concerned with the field of therapeutic genes design and all genetic engineering processes, whether at the levels of diagnosis, treatment or prediction of the occurrence and development of diseases. Recently, the Medical Genetics science has played a major role in the study of genetic factors and their relationship to cancer diseases at the levels of diagnosis, treatment or prediction of the occurrence and development of diseases.