Phosphorus MR spectroscopy shows a tissue specific in vivo distribution of biochemical expression of the G3460A mutation in Leber's hereditary optic neuropathy
- R Lodi1,
- V Carelli2,
- P Cortelli3,
- S Iotti1,
- M L Valentino2,
- P Barboni4,
- F Pallotti5,
- P Montagna2,
- B Barbiroli1
- 1Dipartimento di Medicina Clinica e Biotecnologia Applicata “D Campanacci”, University of Bologna, Bologna, Italy
- 2Istituto di Clinica Neurologica, University of Bologna
- 3Dipartimento di Patologia Neuropsicosensoriale, University of Modena, Modena, Italy
- 4Dipartimento di Oculistica, “Centro Salus”, Bologna, Italy
- 5College of Physicians and Surgeons, Columbia University, New York, USA
- Correspondence to: Dr R Lodi, Dipartimento di Medicina Clinica e Biotecnologia Applicata “D Campanacci”, Universita' di Bologna, Policlinico S Orsola, Via Massarenti 9, 40138 Bologna, Italy; lodi{at}med.unibo.it
- Received 31 October 2001
- Accepted 24 January 2002
- Revised 16 January 2002
Abstract
Occipital lobe and calf muscle energy metabolism were studied in vivo by magnetic resonance spectroscopy (31P-MRS) in four members of a family harbouring the mitochondrial DNA G3460A mutation causing Leber's hereditary optic neuropathy (LHON). Three siblings carried 100% mutated mitochondrial DNA (homoplasmy), while their mother had coexistence of mutated and wild-type mitochondrial DNA (heteroplasmy). Indices of brain energy metabolism on 31P-MRS were abnormal in all subjects examined, but the muscle oxidative phosphorylation rate was normal. These findings indicate a tissue specific distribution of the biochemical expression of the G3460A LHON mutation and suggest that extramitochondrial factors, such as nuclear genes, may influence expression of this mutation in vivo.
