ABSTRACT
Genetic factors are important host factors that play a role in the development of all diseases through their interaction with environmental factors. Most genetic disorders are the direct result of a mutation in a single gene. However, one of the most difficult challenges currently faced by researchers is the identification of ways in which genes contribute to diseases with complex inheritance patterns, such as cancer, diabetes, asthma, and mental illness. In all of these cases, no single gene determines whether a person will develop a disease. Several genes may contribute to an individual's susceptibility to a disease; genes may also affect how an individual reacts to environmental factors. In this study, we attempted to classify high-risk groups using up-to-date genetic knowledge. We also briefly discuss the role of scientific evidence in the identification (through genetic screening) and management of high-risk subgroups in the population.