Linked Life Data

15639197

Source:http://linkedlifedata.com/resource/pubmed/id/15639197

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2005-1-10
pubmed:abstractText
Thymidine kinase 2 (TK2) and deoxyguanosine kinase (dGK) are the two key enzymes in mitochondrial DNA (mtDNA) precursor synthesis. Deficiencies in TK2 or dGK activity, due to genetic alteration, have been shown to cause tissue-specific depletion of mtDNA. In the case of TK2 deficiency, affected individuals suffer severe myopathy and, in the case of dGK deficiency, devastating liver or multi-systemic disease. Here, we report clinical and biochemical findings from two patients with mtDNA depletion syndrome. Patient A was a compound heterozygote carrying the previously reported T77M mutation and a novel mutation (R161K) in the TK2 gene. Patient B carried a novel mutation (L250S) in the dGK gene. The clinical symptoms of patient A included muscular weakness and exercise intolerance due to a severe mitochondrial myopathy associated with a 92% reduction in mtDNA. There was minimal involvement of other organs. Patient B suffered from rapidly progressive, early onset fatal liver failure associated with profoundly decreased mtDNA levels in liver and, to a lesser extent, in skeletal muscle. Site-directed mutagenesis was used to introduce the mutations detected in patients A and B into the TK2 and dGK cDNAs, respectively. We then characterized each of these recombinant enzymes. Catalytic activities of the three mutant enzymes were reduced to about 2-4% for TK2 and 0.5% for dGK as compared to the wild-type enzymes. Altered competition between dCyd and dThd was observed for the T77M mutant. The residual activities of the two mitochondrial enzymes correlated directly with disease development.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1096-7192
pubmed:author
pubmed:issnType
Print
pubmed:volume
84
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
75-82
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:15639197-Child, Preschool, pubmed-meshheading:15639197-Chromatography, Gel, pubmed-meshheading:15639197-DNA, Complementary, pubmed-meshheading:15639197-DNA, Mitochondrial, pubmed-meshheading:15639197-DNA Primers, pubmed-meshheading:15639197-Fatal Outcome, pubmed-meshheading:15639197-Female, pubmed-meshheading:15639197-Humans, pubmed-meshheading:15639197-Infant, Newborn, pubmed-meshheading:15639197-Liver, pubmed-meshheading:15639197-Male, pubmed-meshheading:15639197-Mitochondrial Myopathies, pubmed-meshheading:15639197-Muscle, Skeletal, pubmed-meshheading:15639197-Mutagenesis, Site-Directed, pubmed-meshheading:15639197-Mutation, pubmed-meshheading:15639197-Phosphotransferases (Alcohol Group Acceptor), pubmed-meshheading:15639197-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:15639197-Thymidine Kinase
pubmed:year
2005
pubmed:articleTitle
Molecular insight into mitochondrial DNA depletion syndrome in two patients with novel mutations in the deoxyguanosine kinase and thymidine kinase 2 genes.
pubmed:affiliation
Department of Molecular Bioscience, Section of Veterinary Medical Biochemistry, SLU, The Biomedical Centre, P.O. Box 575, SE-751 23 Uppsala, Sweden. liya.wang@vmk.slu.se
pubmed:publicationType
Journal Article, Case Reports, Research Support, Non-U.S. Gov't