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Neurogenetics

, Volume 2, Issue 2, pp 121–127 | Cite as

Two novel point mutations of mitochondrial tRNA genes in histologically confirmed Parkinson disease

  • Eva M. Grasbon-Frodl
  • Siegfried Kösel
  • Mathias Sprinzl
  • Ulrich von Eitzen
  • Parviz Mehraein
  • M. B. Graeber
Original Article

Mutations in mitochondrially encoded tRNA genes have been described in a variety of neurological disorders. One such mutation, the A to G transition at nucleotide position 4336 of the mitochondrial tRNA(Gln) gene, has been associated with both Alzheimer and Parkinson disease. We have now performed a complete sequence analysis of all 22 mitochondrially encoded tRNA genes in 20 cases of histologically proven idiopathic Parkinson disease. Genomic DNA extracted from the substantia nigra of frozen or formalin-fixed and paraffin-embedded brains was used for amplification by polymerase chain reaction followed by automated sequencing. Two new homoplasmic point mutations were detected in the genes for tRNA(Thr) (15950 G/A) and tRNA(Pro) (15965 T/C) in 1 patient each. Restriction enzyme digestion revealed absence of the 15950 G/A mutation in 96 controls and in 40 cases of neuropathologically confirmed Alzheimer disease. The 15965 T/C mutation was shown to be absent from 100 control subjects and 47 Alzheimer cases. In addition to the two novel mutations, six known sequence variants were detected in a total of 6 different patients in the genes for tRNA(Asp) (G7521A, 1), tRNA(Arg) (T10463C, 1), tRNA(LeuCUN) (A12308G, 2), and tRNA(Thr) (A15924G, 1; G15928A, 2), including 1 patient carrying the tRNA(Gln) (A4336G) mutation. The G15950A transition affects position 70 of the aminoacyl acceptor stem of tRNA(Thr), which has been implicated as a recognition element for threonyl-tRNA synthetase and, at least in some tRNAs, in the processing of primary mitochondrial transcripts. The T15965C point mutation in the mitochondrial tRNA(Pro) gene alters position 64 of the TψC stem. The corresponding nucleotide in bacterial aminoacyl-tRNAs is involved in the interaction with elongation factor Tu. Thus, the two novel mutations are likely to be of functional relevance and could contribute to dopaminergic nerve cell death in affected individuals.

Key words Mitochondrial tRNA genes Point mutations Parkinson disease 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Eva M. Grasbon-Frodl
    • 1
  • Siegfried Kösel
    • 1
  • Mathias Sprinzl
    • 3
  • Ulrich von Eitzen
    • 1
  • Parviz Mehraein
    • 1
  • M. B. Graeber
    • 2
  1. 1.Molecular Neuropathology Laboratory, Institute of Neuropathology, Ludwig-Maximilians-University, D-80337 Munich, GermanyDE
  2. 2.Molecular Neuropathology Laboratory, Department of Neuromorphology, Max-Planck-Institute of Neurobiology, Am Klopferspitz 18a, D-82152 Martinsried, Germany Tel.: 49 89 8578 3666; Fax: 49 89 8995 0077 e-mail: neuropat@neuro.mpg.deDE
  3. 3.Laboratory for Biochemistry, University of Bayreuth, D-95440 Bayreuth, GermanyDE

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