Multisystem disorder associated with a missense mutation in the mitochondrial cytochrome b gene.
Mitochondrial cytochrome b mutations have been reported to have a homogenous phenotype of pure exercise intolerance. We describe a novel mutation in the cytochrome b gene of mitochondrial DNA (A15579G) associated with a selective decrease of muscle complex III activity in a patient who, besides severe exercise intolerance, also has multisystem manifestations (deafness, mental retardation, retinitis pigmentosa, cataract, growth retardation, epilepsy). The point mutation is heteroplasmic in muscle (88%) and leukocytes (15%), and changes a highly conserved tyrosine to cysteine at amino acid position 278.
Wibrand
F
F
John F. Kennedy Institute, Glostrup Denmark.
Ravn
K
K
Schwartz
M
M
Rosenberg
T
T
Horn
N
N
Vissing
J
J
D000328:Adult; D003573:Cytochrome b Group / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics; D004827:Epilepsy / Q000235:genetics; D005260:Female; D006312:Hearing Loss, Bilateral / Q000235:genetics*; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D009135:Muscular Diseases / Q000235:genetics*; D020125:Mutation, Missense; D010641:Phenotype; D012150:Polymorphism, Restriction Fragment Length; D012174:Retinitis Pigmentosa / Q000235:genetics
D003573:Cytochrome b Group; D004272:DNA, Mitochondrial