Mitochondrial DNA depletion syndrome (MDDS) is a rare genetic disorder that affects the mitochondria, the energy-producing structures in cells. It is characterized by a significant reduction in the amount of mitochondrial DNA, which is essential for the proper functioning of these organelles. This depletion can lead to various health issues, including muscle weakness, neurological problems, and organ dysfunction. MDDS can be caused by mutations in specific genes that are involved in mitochondrial DNA maintenance. Symptoms often appear in infancy or early childhood, and the severity can vary widely among affected individuals. Early diagnosis and management are crucial for improving quality of life and addressing complications.