Frequency of mitochondrial transfer RNA mutations and deletions in 225 patients presenting with respiratory chain deficiencies
- Michaela Jakscha,
- Stephanie Kleinleb,
- Curt Scharfec,
- Thomas Klopstockd,
- Dieter Pongratze,
- Josef Müller-Höckerf,
- Klaus-D Gerbitza,
- Sabina Liechti-Gallatib,
- Hanns Lochmullere,
- Rita Horvatha
- aMetabolic Disease Centre Munich-Schwabing and Institute of Clinical Chemistry, Diagnostic Molecular Biology, and Mitochondrial Genetics, Munich, Germany, bHuman Molecular Genetics, Department of Paediatrics and Clinical Research, University of Berne, Switzerland, cGenome Technology Centre, Stanford University, Palo Alto, CA, USA, dDepartment of Neurology, Grosshadern, LMU Munich, Germany, eFriedrich-Baur-Institut, LMU Munich, Germany, fInstitute of Pathology, LMU Munich, Germany
- Dr Jaksch, Academic Hospital Schwabing, Koelner Platz 1, 80804 Muenchen, Germany,Michaela.Jaksch{at}lrz.uni-muenchen.de
- Revised 12 July 2001
- Accepted 18 July 2001
Abstract
OBJECTIVE To evaluate the frequency of pathogenic mtDNA transfer RNA mutations and deletions in biochemically demonstrable respiratory chain (RC) deficiencies in paediatric and adult patients.
METHODS We screened for deletions and sequenced mitochondrial transfer RNA genes in skeletal muscle DNA from 225 index patients with clinical symptoms suggestive of a mitochondrial disorder and with biochemically demonstrable RC deficiency in skeletal muscle.
RESULTS We found pathogenic mitochondrial DNA mutations in 29% of the patients. The detection rate was significantly higher in adults (48%) than in the paediatric group (18%). Only one pathogenic mutation was detected in the neonatal group. In addition, we describe seven novel transfer RNA sequence variations with unknown pathogenic relevance (six homoplasmic and one heteroplasmic) and 13 homoplasmic polymorphisms. One heteroplasmic transfer RNALeu(UUR) A>G mutation at position 3274 is associated with a distinct neurological syndrome.
CONCLUSIONS We provide an estimation of the frequency of mitochondrial transfer RNA mutations and deletions in paediatric and adult patients with respiratory chain deficiencies.
