A juvenile case of MELAS with T3271C mitochondrial DNA mutation.
We present here a patient with muscle fatigue and poor growth since the age of 6 y. The diagnosis of a mitochondrial disease was based on the presence of ragged red fibers in the muscle biopsy and on a combined defect of mitochondrial DNA-encoded respiratory enzymes. Epilepsia partialis continua with stroke-like episodes appeared 2 mo before death at the age of 18 and prompted a search for mitochondrial DNA mutations associated with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes. Minisequencing of the patient's DNA samples revealed a heteroplasmic T3271C mutation with a 78-94% mutation load in her fibroblasts or autopsy-derived tissue samples. This is the ninth reported non-Japanese patient with T3271C mutation. Our patient shows that despite very high proportion of mutant mtDNA, the T3271C mutation can give rise to mild symptoms in childhood and to a rapid terminal phase that simulates encephalitis.
Stenqvist
Laura
L
Department of Neurology, Biomedicum Helsinki, Helsinki University, FIN-00290 Helsinki, Finland. laura.stenqvist@hus.fi
Paetau
Anders
A
Valanne
Leena
L
Suomalainen
Anu
A
Pihko
Helena
H
D000293:Adolescent; D001344:Autopsy; D001706:Biopsy; D001921:Brain / Q000473:pathology; D002648:Child; D004252:DNA Mutational Analysis; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017241:MELAS Syndrome / Q000175:diagnosis* / Q000235:genetics*; D008854:Microscopy, Electron; D009132:Muscles / Q000473:pathology / Q000648:ultrastructure; D009154:Mutation; D010375:Pedigree; D014018:Tissue Distribution
D004272:DNA, Mitochondrial