- Progressive paralysis of certain eye muscles (chronic progressive external ophthalmoplegia, or CPEO);
- Abnormal accumulation of colored (pigmented) material on the retina (atypical retinitis pigmentosa), leading to chronic inflammation and progressive degeneration of the retina; and
- Heart disease (cardiomyopathy) such as cardiac conduction defects and heart block.
Kearns-Sayre syndrome is one of the mitochondrial encephalomyopathies. These disorders are due to defects in the DNA of the mitochondria, the cell structures that produce energy. These defects cause the brain and muscles to function abnormally (encephalomyopathy). In about 80% of cases of Kearns-Sayre syndrome, tests reveal deletions in mitochondrial DNA (mtDNA).
There are many other names for the Kearns-Sayre syndrome including: CPEO with myopathy; CPEO with ragged-red fibers; KSS; Mitochondrial cytopathy, Kearns-Sayre type; Oculocraniosomatic syndrome; Ophthalmoplegia-plus syndrome; Ophthalmoplegia with myopathy; and Ophthalmoplegia with ragged-red fibers.