A new mitochondrial transfer RNAPro gene mutation associated with myoclonic epilepsy with ragged-red fibers and other neurological features.
BACKGROUND
Pathogenic mutations of the human mitochondrial genome are associated with well-characterized, progressive neurological syndromes, with mutations in the transfer RNA genes being particularly prominent.


OBJECTIVE
To describe a novel mitochondrial transfer RNA(Pro) gene mutation in a woman with a myoclonic epilepsy with ragged-red fibers-like disease. Design, Setting, and Patient Case report of a 49-year-old woman presenting with a myoclonic epilepsy with ragged-red fibers-like disease comprising myoclonic jerks, cerebellar ataxia, and proximal muscle weakness.


RESULTS
Histochemical analysis of a muscle biopsy revealed numerous cytochrome-c oxidase-deficient, ragged-red fibers, while biochemical studies indicated decreased activity of respiratory chain complex I. Molecular investigation of mitochondrial DNA revealed a new heteroplasmic mutation in the TpsiC stem of the mitochondrial transfer RNA(Pro) gene that segregated with cytochrome-c oxidase deficiency in single muscle fibers.


CONCLUSIONS
Our case serves to illustrate the ever-evolving phenotypic spectrum of mitochondrial DNA disease and the importance of performing comprehensive mitochondrial genetic studies in the absence of common mitochondrial DNA mutations.
Blakely
Emma L
EL
The Medical School, Newcastle University, Newcastle upon Tyne, Enlgand.
Trip
S Anand
SA
Swalwell
Helen
H
He
Langping
L
Wren
Damian R
DR
Rich
Philip
P
Turnbull
Douglass M
DM
Omer
Salah E
SE
Taylor
Robert W
RW
D030401:Cytochrome-c Oxidase Deficiency / Q000150:complications / Q000235:genetics; D004252:DNA Mutational Analysis / Q000379:methods; D004272:DNA, Mitochondrial / Q000235:genetics*; D042967:Electron Transport Complex I / Q000378:metabolism; D005260:Female; D006801:Humans; D017243:MERRF Syndrome / Q000235:genetics* / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D009154:Mutation; D012361:RNA, Transfer, Pro / Q000235:genetics*; D013385:Succinate Dehydrogenase / Q000378:metabolism
D004272:DNA, Mitochondrial; D012361:RNA, Transfer, Pro; D013385:Succinate Dehydrogenase; D042967:Electron Transport Complex I