Related Experiment Video
Updated: Aug 12, 2025

Engineering and Characterization of an Optogenetic Model of the Human Neuromuscular Junction
Published on: April 14, 2022
KEARNS-SAYRE SYNDROME MASQUERADING AS MYASTHENIA GRAVIS
Jared T Sokol1, Sandra Hoyek1, Anne B Fulton2
1Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts; and.
Purpose:
Kearns-Sayre syndrome (KSS) is a mitochondrial DNA deletion syndrome that is characterized by the triad of onset commonly before age 20, pigmentary retinopathy, and chronic progressive external ophthalmoplegia. Here, we present a case of KSS masquerading as myasthenia gravis.
Methods:
Case report.
Results:
A 15-year-old boy with a presumed diagnosis of myasthenia gravis presented with blurry vision, ophthalmoplegia, and ptosis. He was found to have a mitochondrial pigmentary retinopathy and was eventually diagnosed with KSS after mitochondrial DNA sequencing revealed a novel large-scale deletion of 7.9 kb of mitochondrial DNA from nucleotides 6,578 to 14,460.
Conclusion:
We report a case of KSS found to have a novel large-scale mitochondrial DNA deletion. The presence of a mitochondrial pigmentary retinopathy found on dilated examination led to reconsideration of the previous diagnosis of myasthenia gravis and ultimately led to the correct diagnosis of KSS.
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