Neuroimaging plays a vital role in the diagnosis of mitochondrial neurological disease. Grey matter abnormalities and stroke-like lesions are considered to be signature findings. We report the findings of children with white matter involvement or leukoencephalopathy in a cohort of children with suspected mitochondrial neurological disease.

Aim: To establish the frequency of white matter changes on neuroimaging in a cohort of children with suspected mitochondrial disease.

Method: Retrospective review of children with suspected mitochondrial neurological disorder over a 6 year period (April 2007 to 2013). We collected clinical, neuroimaging, biochemical and molecular genetic data.

Results: In the cohort of 108 children with suspected mitochondrial neurological disease, 54 (50%) had multisystem involvement; opthalmoplegia and cardiac involvement are common comorbidities.

47 (43.5%) had predominantly white matter disease on neuroimaging, consisting of high T2 signal of deep cerebral and periventricular white matter. 30/47 (63%) had isolated white matter changes, 12/47 (25%) had white matter and basal ganglia changes and 5/47 (10%) had atrophy and abnormal white matter.

In the mitochondrial leukoencephalopathy group, a molecular genetic diagnosis was was obtained in 40%, 19/47 (17 nuclear, 2 mitochondrial DNA mutations). In the 28 children without a molecular genetic diagnosis, 17/28 (60%) had abnormal respiratory chain in muscle, 2/28 abnormal muscle histology, 6/9 raised CSF lactate and 7/25 raised plasma lactate.

Conclusion: In our cohort of suspected mitochondrial disorders, leukoencephalopathy is common. The finding of leukoencephalopathy in a child with neurological and multisystem involvement should prompt a thorough evaluation for mitochondrial disease.