Genetic epidemiology is a branch of human genetics that studies the role of genetic factors in the occurrence, distribution, and control of diseases in human populations. It combines principles of genetics, epidemiology, statistics, and population biology to understand how genes and environmental factors interact to influence human health and disease. Unlike traditional epidemiology, which mainly focuses on environmental and social determinants, genetic epidemiology emphasizes the contribution of heredity and genetic variation to disease susceptibility. The major objective of genetic epidemiology is to determine whether a particular disease has a genetic component and to estimate the relative contribution of genetic and environmental factors. It also investigates how diseases are transmitted within families and populations. Diseases such as diabetes, hypertension, asthma, schizophrenia, breast cancer, and several rare genetic disorders may involve both genetic predisposition and environmental