The main role of the mitochondria is to produce energy in the form of adenosine triphosphate (ATP) for the cell, using a collection of proteins that are embedded in the inner mitochondrial membrane known the electron transport chain (ETC).
[4] Stroke-like episodes are a prevalent feature in this syndrome, but do not follow typical vascular stroke patterns in terms of affected brain regions.
With repeated events overtime, there is an accumulation of damage, which results in cognitive decline, including memory difficulties, impaired executive functioning, trouble maintaining attention, and problems with movement or controlling muscles.
Additional neurological symptoms reported include recurring headaches, developmental delay, learning disorders, myoclonus, ataxia, and altered mental status.
[4] Progressive sensorineural hearing loss is another prevalent feature as the mitochondria within the cochlea and neurons making up the auditory neural pathways are unable to provide adequate energy to facilitate sound transmission and perception.
[8] Other common clinical findings include generalized epilepsy, ataxia (poor coordination), myopathy difficulty keeping up with physical activity, dementia, ptosis, optic atrophy, peripheral neuropathy, sensorineural hearing loss, and stunted height.
Additionally, less common clinical manifestations, seen in fewer than fifty percent of patients include cardiomyopathy, pigmentary retinopathy (accumulation of pigments in the retina), pyramidal signs, ophthalmoparesis, multiple lipomas.
[9] When looking at muscle cells of individuals with MERRF under a microscope with special staining, there are an abundance of ragged red fibers present.
These children experience a progressive decline in mental and physical abilities, usually leading to death within 2 to 3 years, due to difficulty breathing.
Symptoms affecting the central nervous system occur because of damage to gray matter tracts, especially in the basal ganglia, thalamus, midbrain, and brainstem.
However, one child may inherit a greater number of mutated mitochondria than his or her sibling, which explains the possibility for symptoms and disease severity to vary among family members.
Management strategies include treating symptoms and performing regular procedures and laboratory testing to detect complications early.
Listed below are several recommended laboratory tests and procedure:[6] - Annual fasting blood glucose - HgA1c - Annual ECG - Biannual echocardiogram - Audiometry (for individuals experiencing hearing loss) It is recommended for patients to perform aerobic exercises, with or without resistance training, to increase stamina, strength, and decrease fatigue.