A mitochondrial DNA mutation in a patient with an extensive family history of Duchenne muscular dystrophy.
One challenge in the molecular diagnosis of mitochondrial DNA (mtDNA) disorders is detection of a low percentage of mutant heteroplasmy. We report a patient who had a delayed molecular diagnosis of mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome due to the complication of an extensive family history of another neuromuscular disease, Duchenne muscular dystrophy, and the failure to detect a low proportion of mutant A3243G mtDNA with a polymerase chain reaction (PCR)/restriction fragment length polymorphism (RFLP)/ethidium bromide detection method. Using an improved, more sensitive allele-specific oligonucleotide (ASO) radioactive dot-blot hybridization method, a low degree of A3243G heteroplasmy was detected in several tissues from this patient. This case underscores the importance of a sensitive mutation detection method and the need for a search for mtDNA mutations if the patient's clinical symptoms suggest a mitochondrial disorder despite the family background of another neuromuscular disease.
Wong
Lee-Jun C
LJ
Molecular Genetics Laboratory, Institute for Molecular and Human Genetics, Georgetown University Medical Center, M4000, 3800 Reservoir Road NW, Washington, DC 20007, USA. wonglj@georgetown.edu
Wladyka
Christopher
C
Mardach-Verdon
Rebecca
R
D000293:Adolescent; D004272:DNA, Mitochondrial / Q000235:genetics*; D005192:Family Health; D005260:Female; D006801:Humans; D017241:MELAS Syndrome / Q000235:genetics*; D008297:Male; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics*; D010375:Pedigree; D017354:Point Mutation
D004272:DNA, Mitochondrial