Understanding Mendelian vs. Polygenic Diseases

Mendelian genetic diseases are caused by a single change in a DNA base pair, leading to specific phenotypes such as sickle cell anemia and cystic fibrosis. In contrast, common chronic diseases like type 2 diabetes and coronary artery disease arise from the interaction of numerous genetic variants, known as polygenic diseases. These disorders involve complex relationships between hundreds of genetic factors that collectively influence disease susceptibility. The polygenic nature of these diseases complicates the search for genetic causes, as it necessitates examining multiple genetic variations rather than focusing on a single gene.