Mitochondrial Ophthalmoplegia Is Not Only due to mtDNA Deletions

With interest, we read an article written by Lee, et al.1 about a retrospective study of 16 patients with ophthalmoplegia as a manifestation of mitochondrial disorder (MID). Five patients were classified as Kearns-Sayre syndrome (KSS), three as KSS-like, and eight as chronic progressive external ophthalmoplegia (CPEO).1 The authors found gastrointestinal abnormalities in five of KSS and KSS-like patients, but in none of CPEO patients; therefore, they concluded that gastrointestinal disease is a feature of KSS.1 We have the following comments and concerns regarding this article