History[edit]
The triad of CPEO, bilateral pigmentary retinopathy, and cardiac conduction abnormalities was first described in a case report of two patients in 1958 by Thomas P. Kearns (1922-2011), MD., and George Pomeroy Sayre (1911-1992), MD.[13] A second case was published in 1960 by Jager and co-authors reporting these symptoms in a 13-year-old boy.[14] Previous cases of patients with CPEO dying suddenly had been published, occasionally documented as from a cardiac dysrhythmia. Other cases had noted a peculiar pigmentation of the retina, but none of these publications had documented these three pathologies occurring together as a genetic syndrome.[15] Kearns published a defining case in 1965 describing 9 unrelated cases with this triad.[15] In 1988, the first connection was made between KSS and large-scale deletions of muscle mitochondrial DNA (abbreviated mtDNA)[16][17] Since this discovery, numerous deletions in mitochondrial DNA have been linked to the development of KSS.[18][19][20]