Yasushi Iimura

The somatic GNAQ mutation c.548G>A (p.R183Q) is consistently found in Sturge–Weber syndrome

Sturge–Weber syndrome (SWS) is a neurocutaneous disorder characterized by capillary malformation (port-wine stains), and choroidal and leptomeningeal vascular malformations. Previously, the recurrent somatic mutation c.548G>A (p.R183Q) in the G-α q gene (GNAQ) was identified as causative in SWS and non-syndromic port-wine stain patients using whole-genome sequencing. In this study, we investigated somatic mutations in GNAQ by next-generation sequencing. We first performed targeted amplicon sequencing of 15 blood–brain-paired samples in sporadic SWS and identified the recurrent somatic c.548G>A mutation in 80% of patients (12 of 15). The percentage of mutant alleles in brain tissues of these 12 patients ranged from 3.6 to 8.9%. We found no other somatic mutations in any of the seven GNAQ exons in the remaining three patients without c.548G>A. These findings suggest that the recurrent somatic GNAQ mutation c.548G>A is the major determinant genetic factor for SWS and imply that other mutated candidate gene(s) may exist in SWS.

Posterior quadrant disconnection surgery for Sturge-Weber syndrome

Some patients with Sturge‐Weber syndrome (SWS) need epilepsy surgery for adequate seizure control and prevention of psychomotor deterioration. The majority of patients with SWS have leptomeningeal angioma located over the temporal, parietal, and occipital lobes. We applied posterior quadrant disconnection surgery for this type of SWS with intractable seizure. We evaluated the efficacy of this procedure in seizure control and psychomotor development.

Sturge-Weber syndrome with spontaneous intracerebral hemorrhage in childhood

A girl aged 2 years 10 months suddenly went into a deep coma and demonstrated left hemiplegia. At birth, she had exhibited a left-sided facial port-wine stain typical of Sturge-Weber syndrome (SWS) and involving the V1 and V2 distributions of the trigeminal nerve. Computed tomography showed a right thalamic hemorrhage with acute hydrocephalus. Magnetic resonance imaging with Gd enhancement 8 months before the hemorrhage had shown a patent superior sagittal sinus (SSS) and deep venous system. Magnetic resonance imaging and MR angiography studies 2 months before the hemorrhage had revealed obstruction of the SSS and right internal cerebral vein (ICV). Given that a digital subtraction angiography study obtained after the hemorrhage did not show the SSS or right ICV, the authors assumed that impaired drainage was present in the deep venous system at that stage. The authors speculated that the patients venous drainage pattern underwent compensatory changes because of the occluded SSS and deep venous collectors, shifting outflow through other cortical venous channels to nonoccluded dural sinuses. Sudden congestion (nearly total to total obstruction) of the ICV may have caused the thalamic hemorrhage in this case, which is the first reported instance of pediatric SWS with intracerebral hemorrhage and no other vascular lesion. Findings suggested that the appearance of major venous sinus occlusion in a child with SWS could be a warning sign of hemorrhage.

Stepwise Synchronization Through the Corpus Callosum Is One Cause of Myoclonic Jerks

BACKGROUND Epileptic myoclonus is generally treated by valproate monotherapy, and this therapy has confirmed efficacy. However, almost 30% of patients with juvenile myoclonic epilepsy (JME) are valproate-resistant. CASE DESCRIPTION A 23-year-old man with a diagnosis of JME had resistance to multiple antiepileptic drugs (AEDs). Stepwise synchronization of bilateral spikes on electroencephalography (EEG) was found shortly before the clinical myoclonus. The anterior two thirds of the corpus callosum were divided. Desynchronization of spikes by the corpus callosotomy arrested the patients myoclonus. CONCLUSIONS Interhemispheric recruitment of epileptic spikes through the corpus callosum may induce synchronization of spikes and myoclonus.

Analysis of Epileptic Discharges from Implanted Subdural Electrodes in Patients with Sturge-Weber Syndrome

Objective Almost two-thirds of patients with Sturge-Weber syndrome (SWS) have epilepsy, and half of them require surgery for it. However, it is well known that scalp electroencephalography (EEG) does not demonstrate unequivocal epileptic discharges in patients with SWS. Therefore, we analyzed interictal and ictal discharges from intracranial subdural EEG recordings in patients treated surgically for SWS to elucidate epileptogenicity in this disorder. Methods Five intractable epileptic patients with SWS who were implanted with subdural electrodes for presurgical evaluation were enrolled in this study. We examined the following seizure parameters: seizure onset zone (SOZ), propagation speed of seizure discharges, and seizure duration by visual inspection. Additionally, power spectrogram analysis on some frequency bands at SOZ was performed from 60 s before the visually detected seizure onset using the EEG Complex Demodulation Method (CDM). Results We obtained 21 seizures from five patients for evaluation, and all seizures initiated from the cortex under the leptomeningeal angioma. Most of the patients presented with motionless staring and respiratory distress as seizure symptoms. The average seizure propagation speed and duration were 3.1 ± 3.6 cm/min and 19.4 ± 33.6 min, respectively. Significant power spectrogram changes at the SOZ were detected at 10–30 Hz from 15 s before seizure onset, and at 30–80 Hz from 5 s before seizure onset. Significance In patients with SWS, seizures initiate from the cortex under the leptomeningeal angioma, and seizure propagation is slow and persists for a longer period. CDM indicated beta to low gamma-ranged seizure discharges starting from shortly before the visually detected seizure onset. Our ECoG findings indicate that ischemia is a principal mechanism underlying ictogenesis and epileptogenesis in SWS.

Strong coupling between slow oscillations and wide fast ripples in children with epileptic spasms: Investigation of modulation index and occurrence rate

Epileptic spasms (ES) often become drug‐resistant. To reveal the electrophysiological difference between children with ES (ES+) and without ES (ES−), we compared the occurrence rate (OR) of high‐frequency oscillations (HFOs) and the modulation index (MI) of coupling between slow and fast oscillations.