What are mitochondrial encephalopathies?

Mitochondrial encephalomyopathy includes chronic progressive extraocular muscle paralysis, KSS syndrome, mitochondrial encephalomyopathy with hyperlactaemia and stroke-like seizures, myoclonic epilepsy with broken red fibers, maternal inherited syndrome, neuropathic ataxia and retinitis pigmentosa syndrome, etc. Mitochondrial encephalomyopathy has many types, first chronic progressive extraocular muscle paralysis, initial symptoms may be eyelid droop and ophthalmoplegia, gradually developing to paralysis of all extraocular muscles. KSS syndrome can manifest as triad, chronic progressive extraocular muscle paralysis, retinitis pigmentosa, cardiac conduction block, while mitochondrial encephalomyopathy with hyperlactaemia and stroke-like attacks can manifest as stroke-like attacks with hemiplegia, migraine, cortical blindness, migraine, nausea, vomiting, recurrent seizures, mental retardation, etc. Myoclonic epilepsy with broken red fibers is generally characterized by myoclonic seizures, cerebellar ataxia, and often combined with mental retardation, hearing impairment, and weakness of the proximal extremities.