Retin Cases Brief Rep. 2022 Dec 22. doi: 10.1097/ICB.0000000000001397. Online ahead of print.
PURPOSE: Kearns-Sayre syndrome (KSS) is a mitochondrial DNA (mtDNA) deletion syndrome that is characterized by the triad of onset commonly before age twenty, pigmentary retinopathy, and chronic progressive external ophthalmoplegia. Here we present a case of KSS masquerading as myasthenia gravis (MG).
METHODS: Case report.
RESULTS: A 15-year-old male with a presumed diagnosis of MG presented with blurry vision, ophthalmoplegia, and ptosis. He was found to have a mitochondrial pigmentary retinopathy and was eventually diagnosed with KSS after mtDNA sequencing revealed a novel large-scale deletion of 7.9kb of mtDNA from nucleotides 6578 to 14,460.
CONCLUSIONS: We report a case of KSS found to have a novel large-scale mtDNA deletion. The presence of a mitochondrial pigmentary retinopathy found on dilated examination led to reconsideration of the previous diagnosis of MG and ultimately led to the correct diagnosis of KSS.