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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 11
pubmed:dateCreated
2008-11-5
pubmed:abstractText
Mitochondrial DNA depletion syndrome (MDS) is a severe recessively inherited disease of childhood. It manifests most often in infancy, is rapidly progressive and leads to early death. MDS is caused by an increasing number of nuclear genes leading to multisystemic or tissue-specific decrease in mitochondrial DNA (mtDNA) copy number. Thymidine kinase 2 (TK2) has been reported to cause a myopathic form of MDS. We report here the clinical, autopsy and molecular genetic findings of rapidly progressive fatal infantile mitochondrial syndrome. All of our seven patients had rapidly progressive myopathy/encephalomyopathy, leading to respiratory failure within the first 3 years of life, with high creatine kinase values and dystrophic changes in the muscle with cytochrome c oxidase-negative fibres. In addition, two patients also had terminal-phase seizures, one had epilepsia partialis continua and one had cortical laminar necrosis. We identified two different homozygous or compound heterozygous mutations in the TK2 gene in all the patients: c.739 C s -> T and c.898 C -> T, leading to p.R172W and p.R225W changes at conserved protein sites. R172W mutation led to myopathy or encephalomyopathy with the onset during the first months of life, and was associated with severe mtDNA depletion in the muscle, brain and liver. Homozygosity for R225W mutation manifested during the second year of life as a myopathy, and showed muscle-specific mtDNA depletion. Both mutations originated from single ancient founders, with Finnish origin and enrichment for the new R172W mutation, and possibly Scandinavian ancestral origin for the R225W. We conclude that TK2 mutations may manifest as infantile-onset fatal myopathy with dystrophic features, but should be considered also in infantile progressive encephalomyopathy with wide-spread mtDNA depletion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1460-2156
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
131
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2841-50
pubmed:meshHeading
pubmed-meshheading:18819985-Amino Acid Sequence, pubmed-meshheading:18819985-Base Sequence, pubmed-meshheading:18819985-Biopsy, pubmed-meshheading:18819985-DNA, Mitochondrial, pubmed-meshheading:18819985-Disease Progression, pubmed-meshheading:18819985-Electron Transport, pubmed-meshheading:18819985-Fatal Outcome, pubmed-meshheading:18819985-Female, pubmed-meshheading:18819985-Haplotypes, pubmed-meshheading:18819985-Homozygote, pubmed-meshheading:18819985-Humans, pubmed-meshheading:18819985-Infant, pubmed-meshheading:18819985-Male, pubmed-meshheading:18819985-Mitochondrial Myopathies, pubmed-meshheading:18819985-Molecular Sequence Data, pubmed-meshheading:18819985-Muscle, Skeletal, pubmed-meshheading:18819985-Mutation, Missense, pubmed-meshheading:18819985-Species Specificity, pubmed-meshheading:18819985-Thymidine Kinase
pubmed:year
2008
pubmed:articleTitle
Thymidine kinase 2 defects can cause multi-tissue mtDNA depletion syndrome.
pubmed:affiliation
Research Programme of Molecular Neurology, Biomedicum-Helsinki, University of Helsinki, Helsinki, Finland.
pubmed:publicationType
Journal Article, Case Reports, Research Support, Non-U.S. Gov't