A hereditary disease, also known as an inherited disease or genetic disorder, is a disease caused by changes in ones genetic material (DNA) that are passed down from generation to generation. Genetic disorders can be caused by a mutation in one gene (monogenic disorder), by mutations in multiple genes (multifactorial inheritance disorder), by a combination of gene mutations and environmental factors, or by damage to chromosomes. There are many types of hereditary diseases, and some of the most common ones include skin cancer, deafness present at birth, Duchenne muscular dystrophy, familial hypercholesterolemia, hemochromatosis, neurofibromatosis type 1, sickle cell disease, and Tay-Sachs disease. Genetic studies allow the identification of genes related to and/or responsible for a specific pathology, and they allow personalized attention to each patient and determine the risk in those cases with a family history of the disease.