Cerebral magnetic resonance spectroscopy in Rett syndrome. Failure to detect mitochondrial disorder.

A total of eight girls with Rett syndrome were examined, by 31phosphorous magnetic resonance spectroscopy (31P MRS) (4 girls), proton MRS (1H MRS) (4 girls), muscle biopsying (2 girls), and determination of pyruvate and lactate in plasma (5 girls), to investigate the hypothesis of a mitochondrial malfunction as the etiology for this neurologic disorder. Almost all examinations, including electron microscopy in search of structural mitochondrial abnormalities, gave normal results, the only exception being the not unexpected finding of slight neurogenic atrophy in the muscle biopsy specimen from a 15-year-old girl.