"Ragged Red Fibers" - clumps of diseased mitochondria accumulate in the subsarcolemmal region of the muscle fiber and appear as "Ragged Red Fibers" when muscle is stained with modified Gömöri trichrome stain
The MERRF syndrome is caused by a maternally-inherited mutation at position 8344 in the mitochondrial genome in over 80% of cases. This point mutation disrupts the mitochondrial gene for tRNA-Lys and so disrupts synthesis of proteins essential for oxidative phosphorylation.
Like many mitochondrial diseases, there is no cure for MERRF and treatment is primarily symptomatic. High doses of Coenzyme Q10 and L-Carnitine have been tried with little success as therapies in hopes of improving mitochondrial function.