Kearns-Sayre syndrome is a rare genetic disorder caused by mitochondrial DNA mutations. It primarily affects the muscles and eyes, leading to symptoms such as progressive weakness, heart problems, and vision issues like ptosis (drooping eyelids) and retinitis pigmentosa (a degenerative eye disease). This syndrome typically appears before the age of 20 and can also involve neurological problems. Diagnosis often involves genetic testing and clinical evaluation. While there is no cure, management focuses on treating symptoms and improving quality of life through supportive therapies and regular monitoring.