Genetic Epidemiology

genetic epidemiology, the study of how genes and environmental factors influence human traits and human health and disease. Genetic epidemiology developed initially from population genetics, specifically human quantitative genetics, with conceptual and methodological contributions from epidemiology.

One of the early proponents of genetic epidemiology, American geneticist Newton Morton, defined the field as one that addresses the etiology, distribution, and control of disease in groups of related individuals and the inherited causes of diseases in populations. That definition later was broadened to include the role of the environment, owing to the realization that genetic factors frequently interact with environmental factors to influence disease in human populations. In 2003, scientists Muin J. Khoury, Julian Little, and Wylie Burke coined the term human genome epidemiology to encompass a system of study that uses the methods of epidemiology to understand the influence of genomic variation in both health and disease, thereby going beyond the influence of individual genes, which remained the primary focus of genetic epidemiology.

Modern genetic epidemiology includes all diseases, whether they are common and complex or supposedly simpler, such as the so-called monogenic (single-gene) disorders. Many advances in the epidemiology of genetic diseases have involved seemingly simple inherited disorders (e.g., cystic fibrosis, sickle cell disease). However, those advances have also indicated that even monogenic disorders can be highly complex, owing to epigenetic factors and interactions of disease genes with environmental factors. In addition to the broad focus on genetic disease, genetic epidemiology encompasses a variety of aspects of epidemiology, including studies of prevalence, clinical epidemiology, genotype-phenotype relationships, and disease progression and outcomes.