RT Journal Article SR Electronic T1 Single Large-Scale Mitochondrial Deletion Syndromes: Neuroimaging Phenotypes and Longitudinal Progression in Pediatric Patients JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology DO 10.3174/ajnr.A8670 A1 Alves, Cesar A.P.F. A1 Rossi-Espagnet, Maria Camilla A1 Perez, Francisco A1 Manteghinejad, Amirreza A1 Peterson, James T. A1 Ganetzky, Rebecca A1 Napolitano, Antonio A1 Grassi, Francesco A1 George-Sankoh, Ibrahim A1 Yildiz, Harun A1 Muraresku, Colleen A1 Falk, Marni J. A1 Martinelli, Diego A1 Longo, Daniela A1 Vanderver, Adeline A1 Gandolfo, Carlo A1 Saneto, Russell P. A1 Goldstein, Amy A1 Vossough, Arastoo YR 2025 UL http://www.ajnr.org/content/early/2025/05/02/ajnr.A8670.abstract AB BACKGROUND AND PURPOSE: Single large-scale mitochondrial deletion syndrome (SLSMD) comprises devastating mitochondrial diseases often classified into 3 major clinical syndromes: Kearns-Sayre syndrome (KSS), chronic progressive external ophthalmoplegia (CPEO), and Pearson syndrome (PS). Nevertheless, there remains large clinical variability and overlap among these SLSMD groups. Therefore, further stratification is required for more precise prognostication and clinical management. Through detailed description and analysis of longitudinal neuroimaging changes, we sought to determine the neuroradiologic hallmarks of SLSMDs and define their expected imaging progression to further delineate their natural history.MATERIALS AND METHODS: A retrospective, longitudinal study of 40 children with SLSMDs at 3 mitochondrial disease centers was performed. MRI review assessed the prevalence and progression of brain lesions in different regions with statistical significance testing and Kaplan-Meier analysis. Hierarchical cluster analysis was performed for involved brain regions to stratify findings into imaging phenotype groups.RESULTS: Among 40 patients with SLSMD (median age 9.26 years; interquartile range: 5.16–13.1), 67.5% had KSS, 15% had KSS with a prior history of PS (PS→KSS), and 10% had PS only. A well-delineated phenotype could not be specified for 1 (2.5%) and 2 (5%) individuals who had CPEO-plus (CPEO + extraocular symptoms). Regardless of presentation, initial MRI of patients with KSS revealed lesions within selective areas of the upper brainstem tegmentum. Follow-up MRIs in 26 patients showed well-defined progression along other select brainstem and white matter regions. Log-rank tests demonstrated varying onset times by lesion type. Cluster analysis revealed 2 distinct neuroimaging groups: 1) KSS, CPEO-plus, and PS→KSS versus 2) PS and not otherwise specified individuals. KSS, CPEO-plus, and PS→KSS showed indistinguishable neuroimaging features regardless of the initial clinical presentation.CONCLUSIONS: We describe the first comprehensive longitudinal neuroimaging pattern analysis in a multicenter, international SLSMDs disease pediatric cohort, delineating a predictable progression of brain lesions, regardless of clinical phenotype.CPEOchronic progressive external ophthalmoplegiaGPglobus pallidusIQRinterquartile rangeKSSKearns-Sayre syndromeNOSnot otherwise specifiedmtDNAmitrochondrial DNAPSPearson syndromePS→KSSindividuals with initial presentation of PS converting to KSS during the progression of the diseaseSLSMDsingle large-scale mitochondrial deletion syndrome