The authors report an abnormal prolonged restricted magnetic resonance imaging (MRI) proton diffusion that persisted for more than 2 years in a 6.5-year-old boy with a progressive neurological disease characterized by developmental retardation, peripheral polyneuropathy, and bilateral optical nerve atrophy. The long-term restricted magnetic resonance imaging proton diffusion observed in diffusion-weighted magnetic resonance images indicates chronic metabolic tissue impairment in the affected white matter, whereas measurable lactate accumulation in proton magnetic resonance spectroscopy was absent, and no respiratory complex abnormality was found in muscle tissue. These findings are suggestive of a chronically disturbed regulation of energy supply triggering a "slow onset" excitotoxicity, causing chronic hypoxia and leading to slow cell death as has been postulated in certain neurodegenerative processes.
