title: When should MELAS (Mitochondrial myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like episodes) be the diagnosis?
abstract: Mitochondrial myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) is a rare mitochondrial disorder. Diagnostic criteria for MELAS include typical manifestations of the disease: stroke-like episodes, encephalopathy, evidence of mitochondrial dysfunction (laboratorial or histological) and known mitochondrial DNA gene mutations. Clinical features of MELAS are not necessarily uniform in the early stages of the disease, and correlations between clinical manifestations and physiopathology have not been fully elucidated. It is estimated that point mutations in the tRNALeu(UUR) gene of the DNAmt, mainly A3243G, are responsible for more of 80% of MELAS cases. Morphological changes seen upon muscle biopsy in MELAS include a substantive proportion of ragged red fibers (RRF) and the presence of vessels with a strong reaction for succinate dehydrogenase. In this review, we discuss mainly diagnostic criterion, clinical and laboratory manifestations, brain images, histology and molecular findings as well as some differential diagnoses and current treatments.
authors.affiliation: Departamento de Clínica Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, PR, Brazil.
authors.forename: Paulo José
authors.initials: PJ
authors.lastname: Lorenzoni
authors.affiliation: Departamento de Clínica Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, PR, Brazil.
authors.forename: Lineu Cesar
authors.initials: LC
authors.lastname: Werneck
authors.affiliation: Departamento de Clínica Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, PR, Brazil.
authors.forename: Cláudia Suemi Kamoi
authors.initials: CS
authors.lastname: Kay
authors.affiliation: Departamento de Clínica Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, PR, Brazil.
authors.forename: Carlos Eduardo Soares
authors.initials: CE
authors.lastname: Silvado
authors.affiliation: Departamento de Clínica Médica, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, PR, Brazil.
authors.forename: Rosana Herminia
authors.initials: RH
authors.lastname: Scola
mesh_terms: D001706:Biopsy; D003937:Diagnosis, Differential; D006801:Humans; D017241:MELAS Syndrome / Q000175:diagnosis* / Q000235:genetics / Q000503:physiopathology / Q000628:therapy; D008279:Magnetic Resonance Imaging; D009154:Mutation