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The electrographic hallmark of childhood absence seizures is 3 Hz generalized spike and wave discharges; however, there is likely a focal thalamic or cortical onset that cannot be detected using scalp electroencephalography (EEG). The purpose of this study was to study the earliest preictal changes in children with absence epilepsy. In this report, magnetoencephalography recordings of 44 absence seizures recorded from 12 children with drug-naïve childhood absence seizures were used to perform time frequency analysis and source localization prior to the onset of the seizures. Evidence of preictal magnetoencephalography frequency changes were detected a mean of 694 ms before the initial spike on the EEG. A consistent pattern of focal sources was present in the frontal cortex and thalamus during this preictal period, but source localization occurred synchronously so that independent activity between the 2 structures could not be distinguished. [ABSTRACT FROM AUTHOR]

Leigh syndrome, due to a dysfunction of mitochondrial energy metabolism, is a genetically heterogeneous and progressive neurologic disorder that usually occurs in infancy and childhood. Its clinical presentation and neuroimaging findings can be variable, especially early in the course of the disease. This report presents a patient with infantile Leigh syndrome who had atypical radiologic findings on serial neuroimaging studies with early and severe involvement of the cervical spinal cord and brainstem and injury to the thalami and basal ganglia occurring only late in the clinical course. Postmortem microscopic examination supported this timing of injury within the central nervous system. In addition, mitochondrial deoxyribonucleic acid sequencing showed a novel homoplasmic variant that could be responsible for this unique lethal form of Leigh syndrome. [ABSTRACT FROM PUBLISHER]

Deletions of chromosome 17p13.3 result in neuronal migration defects such as isolated lissencephaly sequence and Miller-Dieker syndrome. LIS1 is the deleted gene within this region and is thought to directly cause isolated lissencephaly sequence and contribute to Miller-Dieker syndrome. Two additional genes (14-3-3ε and CRK) on the telomeric end of chromosome 17p reportedly contribute to the severe phenotype of Miller-Dieker syndrome. We report 2 patients with deletions of chromosome 17p13.3 involving the genes 14-3-3ε and CRK but not LIS1 with previously unreported, identical phenotypes of macrocephaly, small stature, dysmorphic features, generalized epilepsy, developmental delay, and nonspecific white matter changes. The findings in this report suggest that patients who have deletions of 14-3-3ε and/or CRK should be monitored closely for the development of seizures. [ABSTRACT FROM AUTHOR]