Although the incidental association of OT and C10orf2 TWINKLE mutation is possible, the simultaneous onset of OT and eyelid ptosis at a much younger age than usually observed for OT raises the possibility of mitochondrial dysfunction and loss of mitochondrial DNA integrity in the pathogenesis of OT.
Autosomal dominant progressive external ophthalmoplegia due to the p.R357PPEO1 mutation is a late-onset ocular myopathy beginning with ptosis and progressing slowly.