Timothy C. Hain, MD Page last modified: January 1, 2017
Kearns-Sayre syndrome (abbreviated KSS) is a disease caused by a deletion in the mitochondrial DNA. It is a "progressive external ophthalmoplegia", or PEO. The "external" in the PEO, means that the pupil continues to react (as it is "internal"), but the eye muscles are paralyzed (the external part). Mitochondrial deletions occur in roughly 1/8000 persons, so KSS is rare (Chinnery et al., 2004).
KSS and PEO are distinct from "bulbar palsies", because KSS and PEO involve the eyes alone, while bulbar palsies involve more muscles in the face.
The essence of diagnosting KSS lies in noting a PEO developing before the age of 20 years of age, with ptosis (droopy eyelids), accompanied by retinitis pigmentosa. KSS may affect either gender. Although mitochondrial disorders are usually inherited from the mother, in KSS, this pattern is generally not found.
In PEO, the eyes don't move under ANY circumstances -- neither voluntarily or reflexively. In PEO, there is no "dolls head reflex". See the movie below for an example.
Supplemental material on the site DVD: Movie of PEO due to Kearns-Sayre syndrome.
Supplemental material on the site DVD: Another Movie of PEO due to mitochondiral myopathy. Muscle biopsy showed COX deficient and ragged red fibers. Courtesy of Dr. Dario Yacovino.
Accompanying the PEO can be cardiac conduction problems (i.e. heart arrythmia), ataxia and cerebellar signs (Vedanarayanan, 2003), deafness (Kokotas et al, 2007), and brainstem disorders. White matter disorders are always present in KSS (Filostito, 2007). Cyclic vomiting is rarely encountered in KSS (Boles, 2007)
Muscle biopsy in KSS as well as other mitochondrial myopathies shows "ragged red" fibers.
There are a rather alarming number of references concerning Kearns-Sayre in the literature (more than 500 in Pubmed as of April, 2009).
As is the case for most genetic disorders, at present all we have is supportive treatment. Vigilance is needed regarding the cardic disorders as a pacemaker may be indicated at some point, surgery may be needed to correct eye lid weakness, and hearing aids are commonly used for the hearing loss when it occurs.
Several authors (Rodriguez et al 2007, Komura, 2003; Choi et al, 2000) suggested a benefit for nutritional supplements such as creatine or coenzyme-Q. As there are potential adverse health effects of creatine, we suggest that persons with KSS who wish to pursue this treatment do this under supervision of a physician who is familiar with KSS (and there are not very many of these !).