Treatment with folinic acid can in some cases alleviate the associated symptoms and partially correct associated brain abnormalities, especially if started early in the course of illness. The proposed cause of cerebral folate deficiency in the Kearns–Sayre syndrome is the failure of the mechanisms in the choroid plexus that are responsible for passage of folates from the serum to the cerebrospinal fluid. Cause and prevalence
As characterized in Kearns original publication in 1965 and in later publications, inconsistent features of KSS that may occur are weakness of facial, pharyngeal, trunk, and extremity muscles, hearing loss, small stature, electroencephalographic changes, cerebellar ataxia and elevated levels of cerebrospinal fluid protein.Kearns–Sayre syndrome occurs spontaneously in the majority of cases. In some cases it has been shown to be inherited through mitochondrial, autosomal dominant, or autosomal recessive inheritance. There is no predilection for race or sex, and there are no known risk factors. As of 1992 there were only 226 cases reported in published literature. Although NIH and other studies estimate occurrence in the population to be 1–3 and some as high as 9 in 100,000 individuals but a failure to be referred to specialist centres and recognise the disease symptoms is common

Genetics
KSS is the result of deletions in mitochondrial DNA (mtDNA) that cause a particular constellation of medical signs and symptoms. mtDNA is transmitted exclusively from the mothers ovum. Mitochondrial DNA is composed of 37 genes found in the single circular chromosome measuring 16,569 base pairs in length.
Rufinamide is an anticonvulsant medication. It is used in combination with other medication and therapy to treat Lennox–Gastaut syndrome and various other seizure disorders. Rufinamide, a triazole derivative, was developed in 2004 by Novartis Pharma, AG, and is manufactured by Eisai. Rufinamide was approved by the US Food and Drug Administration (FDA) on November 14, 2008, as adjunctive treatment of seizures associated with Lennox-Gastaut syndrome in children four years and older and adults. Its official FDA-approved labeling does not mention use in the treatment of partial seizures inasmuch as clinical trials submitted to the FDA were marginal. However, several recent clinical trials suggest that the drug has efficacy for partial seizures  It is marketed under the brand name Banzel. It is also marketed in the European Union under the brand name Inovelon.The mechanism of action of rufinamide is not fully understood. There is some evidence that rufinamide can modulate the gating of voltage-gated sodium channels, a common target for antiepileptic drugs. A recent study indicates subtle effects on the voltage-dependence of gating and the time course of inactivation in some sodium channel isoforms that could reduce neuronal excitability. However, this action cannot explain the unique spectrum of activity of rufinamide. References
External links
"Rufinamide". Drug Information Portal. U.S. National Library of Medicine.