Succinate dehydrogenase-deficient leukoencephalopathy is a complex II-related mitochondrial disorder for which the clinical phenotype, neuroimaging pattern and genetic findings have not been comprehensively reviewed.
19 individuals with succinate dehydrogenase deficiency-related leukoencephalopathy were reviewed for neuroradiologic, clinical and genetic findings as part of Institutional Review Board approved studies at Children’s National Health System (Washington, DC) and VU University Medical Center (Amsterdam, NL).
All individuals had signal abnormalities in the central corticospinal tracts and spinal cord where imaging was available. Other typical findings were involvement of the cerebral hemispheric white matter with sparing of the U fibers, the corpus callosum with sparing of the outer blades, the basis pontis, middle cerebellar peduncles and cerebellar white matter, and elevated succinate on MRS. The thalamus was involved in most studies with a predilection for the anterior nucleus, pulvinar and geniculate bodies. Clinically, infantile-onset neurological regression with partial recovery and subsequent stabilization was typical. All individuals had mutations in SDHA, SDHB or SDHAF1, or proven biochemical defect.
Succinate dehydrogenase deficiency is a rare leukoencephalopathy, for which improved recognition by MRI in combination with advanced sequencing technologies allows non-invasive diagnostic confirmation. The MRI pattern is characterized by cerebral hemispheric white matter abnormalities with sparing of the U fibers, corpus callosum involvement with sparing of the outer blades, and involvement of corticospinal tracts, thalami and spinal cord. In individuals with infantile regression and this pattern of MRI abnormalities, the differential diagnosis should include succinate dehydrogenase deficiency, in particular if MRS shows elevated succinate. This article is protected by copyright. All rights reserved.
© 2015 American Neurological Association.