iarjmsIARJMSIARJMS2708-359410.47310/iarjms.2020.v01i02.019External ophthalmoplegia plus due to the variants m.5669G>A respectively m.5702delA in MT-TNJosefFinstererKlinik Landstrasse, Messerli Institute, Vienna, AustriaWe read with interest the article by Visuttijai et al. (2020) on two unrelated patients with progressive external ophthalmoplegia (PEO) due to novel variants in the MT-TN gene. The authors concluded that these variants are pathogenic and that MT-TN is a mutation hot spot for sporadic PEO. However, we raise several concerns. First, the pathogenicity of the variants was assessed without applying the Yarham score, a standardized method for evaluating mitochondrial tRNA mutations. Our application of the modified Yarham score classifies the variants as only "possibly pathogenic." Additionally, the study focuses solely on extraocular symptoms of PEO, yet both patients exhibited manifestations beyond the eye muscles, suggesting they had PEO plus. We believe the study would benefit from a more thorough investigation of multisystem involvement and further evidence supporting the pathogenicity of the MT-TN variants. Such investigations should include brain imaging, neurologic, and organ system assessments to identify subclinical manifestations typical of PEO plus.