Myasthenia graves-like symptoms associated with rare mitochondrial mutation (m.5728T>C)

We report here on a patient who presented with myasthenia gravis type symptoms (fatigable ptosis, increased jitter on single fiber EMG, and a thymic mass) who was subsequently diagnosed with a mitochondrial myopathy. Sequencing of the mitochondrial genome (mtDNA) identified a transition variant in the tRNA asparagine gene (MT-TN) (m.5728T>C) at in 41% of mtDNA molecules in muscle tissue. The variant was not detectable in blood. The m.5728T>C …