Association of the MELAS m.3243A>G mutation with myositis and the superiority of urine over muscle, blood and hair for mutation detection.
A patient with a known family history of mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) due to the MT-TL1 m.3243A>G mutation presented with mild myalgia and very minor upper limb proximal muscle weakness. Muscle histology revealed low levels of cytochrome oxidase-negative fibres and non-specific myositis. Using the last "hot cycle" polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP), the MELAS MT-TL1 m.3243A>G mutation was only detected in urine, and not in hair, blood or skeletal muscle. This report highlights the need to screen various tissues to achieve an accurate mitochondrial genetic diagnosis and suggests the likelihood of myositis arising secondary to the MELAS MT-TL1 m.3243A>G mutation.
Marotta
Rosetta
R
St Vincent's Melbourne Neuromuscular Diagnostic Laboratory, Department of Clinical Neurosciences, 5th Floor Daly Wing, St Vincent's Hospital, 35 Victoria Parade, Fitzroy, Victoria 3065, Australia. rosetta.marotta@svhm.org.au
Reardon
Katrina
K
McKelvie
Penny A
PA
Chiotis
Maria
M
Chin
Judy
J
Cook
Mark
M
Collins
Steven J
SJ
D001706:Biopsy; D004272:DNA, Mitochondrial / Q000235:genetics; D005260:Female; D006197:Hair / Q000737:chemistry*; D006801:Humans; D017241:MELAS Syndrome / Q000175:diagnosis / Q000235:genetics* / Q000652:urine*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000473:pathology; D009154:Mutation; D012150:Polymorphism, Restriction Fragment Length; D020133:Reverse Transcriptase Polymerase Chain Reaction
D004272:DNA, Mitochondrial