Kearns-Sayer syndrome
Last reviewed 09/2021
The Kearns-Sayer syndrome is caused by a somatic insertion or deletion mutation in the mitochodrial genome.
The severity of the syndrome is very variable, depending on the proportion of mitochondria containing mutated DNA. Invariably the disease becomes more severe with age.
KSS may be considered as a severe form of chronic external ophthalmoplegia.