Stiripentol open study in Japanese patients with Dravet syndrome.

PURPOSE: To survey the treatment situation of Dravet syndrome in Japan and to compare this result with effectiveness of stiripentol (STP) add-on therapy in an open-label multicenter study. METHODS: Medical records of patients with Dravet syndrome who visited the study institutions during 2006 were surveyed to examine the effect of antiepileptic drugs (AEDs) on clonic or tonic-clonic seizures (GTCS). Patients older than 1 year of age treated with at least one conventional AED and more than four GTCS per month were invited to participate in the STP study. Seizure status and adverse effects during the first 4 weeks of STP (50 or 1,000 mg/day) add-on therapy (early period) and during long-term treatment were compared with baseline. RESULTS: Only 15% of the treatment trials with 15 conventional AEDs in 112 patients succeeded in reducing seizures by more than 50%. With STP, GTCS were reduced more than 50% in 14 of 23 patients (61%), including 2 who became seizure-free, in the early period. Moreover, duration of seizures was shortened in 10 patients and status epilepticus decreased in 6. These effects continued in the long-term although to a lesser degree. Adverse effects (loss of appetite, sleep disturbance, ataxia, hyperactivity/irritability) disappeared after dose modification in most cases. STP was effective at a lower than initial dose in five patients. Some patients benefited from STP added on clobazam despite mutation in CYP2C19. CONCLUSION: Our data suggest that an early introduction of STP into Japan will result in substantial patient benefit.

Seizure manifesting as a reaching/grasping movement in a patient with post-traumatic epilepsy.

Electrical stimulation (ES) of the pre-supplementary or cingulate motor area can cause reaching/grasping (R/G) movements with the hand contralateral to the side of the brain receiving the ES. We report this phenomenon occurring in a 23-year-old right-handed man during spontaneous epileptic seizure, which developed after traumatic brain injury.

A nonsense mutation of the sodium channel gene SCN2A in a patient with intractable epilepsy and mental decline.

Mutations, exclusively missense, of voltage-gated sodium channel alpha subunit type 1 (SCN1A) and type 2 (SCN2A) genes were reported in patients with idiopathic epilepsy: generalized epilepsy with febrile seizures plus. Nonsense and frameshift mutations of SCN1A, by contrast, were identified in intractable epilepsy: severe myoclonic epilepsy in infancy (SMEI). Here we describe a first nonsense mutation of SCN2A in a patient with intractable epilepsy and severe mental decline. The phenotype is similar to SMEI but distinct because of partial epilepsy, delayed onset (1 year 7 months), and absence of temperature sensitivity. A mutational analysis revealed that the patient had a heterozygous de novo nonsense mutation R102X of SCN2A. Patch-clamp analysis of Na(v)1.2 wild-type channels and the R102X mutant protein coexpressed in human embryonic kidney 293 cells showed that the truncated mutant protein shifted the voltage dependence of inactivation of wild-type channels in the hyperpolarizing direction. Analysis of the subcellular localization of R102X truncated protein suggested that its dominant negative effect could arise from direct or indirect cytoskeletal interactions of the mutant protein. Haploinsufficiency of Na(v)1.2 protein is one plausible explanation for the pathology of this patient; however, our biophysical findings suggest that the R102X truncated protein exerts a dominant negative effect leading to the patient's intractable epilepsy.

A long-term follow-up of zonisamide monotherapy.

OBJECTIVES: Several studies have reported the safety and efficacy of zonisamide monotherapy, but studies on its long-term outcomes are limited. This chart review was conducted to evaluate the long-term outcomes of zonisamide monotherapy. METHODS: The charts were reviewed for 77 patients treated with zonisamide as monotherapy for 6-180 months between May 1985 and December 2003. Outcomes were analyzed by the following subcategories: patients with newly diagnosed epilepsy or with antiepileptic drug-resistant epilepsy, the type of epilepsy, patient age, and treatment period. RESULTS: Of a total of 77 patients, 49 patients (64%) attained 50% or more reduction of seizure frequency and of those patients 38 (49%) attained 75% or more reduction, with 18 patients (24%) becoming seizure-free from 6 to 180 (median 80.6 +/- 43.6) months of follow-up. Thirty-eight patients (49%) continued zonisamide monotherapy as of December 2003. Proportions of patients having 75% or more reduction in seizure frequency in subcategories were as follows; 56% in patients with newly diagnosed epilepsy and 48% in patients whose treatment was switched to zonisamide monotherapy owing to lack of efficacy of or adverse reaction to previous antiepileptic drugs; 60% in patients with localization-related epilepsies and 38% in patients with generalized epilepsies; and 49% in pediatric patients and 50% in adult patients. CONCLUSION: Long-term zonisamide monotherapy was efficacious in a wide range of patients with epilepsy. Zonisamide did not seem to exhibit a reduction in efficacy during long-term use of up to 180 months.

Vaccination and infection as causative factors in Japanese patients with Rasmussen syndrome: molecular mimicry and HLA class I.

Rasmussen syndrome is an intractable epilepsy with a putative causal relation with cellular and humoral autoimmunity. Almost half of the patients have some preceding causative factors, with infections found in 38.2%, vaccinations in 5.9% and head trauma in 8.9% of Japanese patients. In a patient with seizure onset after influenza A infections, cross-reaction of the patient's lymphocytes with GluR epsilon 2 and influenza vaccine components was demonstrated by lymphocyte stimulation test. Database analyses revealed that influenza A virus hemagglutinin and GluR epsilon 2 molecules contain peptides with the patient's HLA class I binding motif (HLA - A*0201). The relative risks of HLA class I genotypes for Rasmussen syndrome are 6.1 (A*2402), 6.4 (A*0201), 6.3 (A*2601) and 11.4 (B*4601). The relative risks of HLA class I-A and B haplotypes are infinity (A*2601 + B*5401), 21.1 (A*2402 + B*1501), 13.3 (A*2402 + B*4801) and 5.1 (A*2402 + B*5201). Some alleles and haplotypes of HLA class I may be the risk factors in Japanese patients. Cross-reactivity of cytotoxic T lymphocytes may contribute to the processes leading from infection to the involvement of CNS.

Autoantibodies and cell-mediated autoimmunity to NMDA-type GluRepsilon2 in patients with Rasmussen's encephalitis and chronic progressive epilepsia partialis continua.

PURPOSE: To evaluate antibody-mediated and cytotoxic T cell-mediated pathogenicity that has been implicated as the autoimmune pathophysiological mechanism in Rasmussen's encephalitis. METHODS: We examined autoantibodies against the N-methyl-d-aspartate glutamate receptor (NMDA-type GluR) epsilon2 subunit and its epitopes in serum and CSF samples from 20 patients [five histologically proven (definitive) Rasmussen's encephalitis with epilepsia partialis continua (EPC), four definitive Rasmussen's encephalitis without EPC, and 11 clinical Rasmussen's encephalitis with EPC]. We examined 3H-thymidine uptake into lymphocytes after stimulation by GluRs. RESULTS: All nine definitive patients (five patients with EPC and four without EPC), and 10 of 11 clinical Rasmussen's encephalitis patients had the autoantibodies. In four patients, the autoantibodies were absent in early stage when epileptic seizures had already become frequent, and appeared subsequently. In two patients, the autoantibodies persisted in the serum after frontal lobe resection or functional hemispherectomy, although epileptic seizures were completely controlled. Autoantibodies to the C2 epitope predominated, while autoantibodies to the extracellular N epitope were rare. The mean 3H-thymidine uptake ratios (stimulation by GluRepsilon2-containing homogenates/stimulation by PHA) were significantly higher in definitive and clinical Rasmussen encephalitis patients than in controls. The mean 3H-thymidine uptake ratios (relative to PHA) were significantly higher for GluRepsilon2-containing homogenate than for control homogenate or GluRdelta2-containing homogenate. CONCLUSIONS: Autoantibodies against GluRepsilon2 may be one of the diagnostic markers for Rasmussen's encephalitis with and without EPC. Patients have activated T cells stimulated by GluRepsilon2 in peripheral blood circulation. We speculate that cellular autoimmunity and the subsequent humoral autoimmunity against GluRepsilon2 may contribute to the pathophysiological processes in Rasmussen's encephalitis.

Mutations of sodium channel alpha subunit type 1 (SCN1A) in intractable childhood epilepsies with frequent generalized tonic-clonic seizures.

A group of infant onset epilepsies manifest very frequent generalized tonic-clonic seizures (GTC) intractable to medical therapy, which may or may not be accompanied by minor seizures such as myoclonic seizures, absences and partial seizures. They include severe myoclonic epilepsy in infancy (SMEI) and intractable childhood epilepsy with GTC (ICEGTC). They are commonly associated with fever-sensitivity, family history of seizure disorders and developmental decline after seizure onset. Mutations of the neuronal voltage-gated sodium channel alpha subunit type 1 gene (SCN1A) were recently reported in SMEI patients. To clarify the genotypic differences in this group of epilepsies, we searched for SCN1A abnormalities in 25 patients with SMEI and 10 with ICEGTC, together with the family members of 15 patients. Frameshift mutations in SCN1A were observed in four patients, nonsense mutations in five patients, missense mutations in 21 patients, other mutations in two patients and no mutation in five patients. SMEI patients showed nonsense mutations, frameshifts, or missense mutations, while ICEGTC patients showed only missense mutations. Study of both parents of 11 patients revealed that the mutations in these patients were de novo. However, two mothers had the same missense mutations as their ICEGTC children, and they had generalized epilepsy with febrile seizures plus. Here we suggest that SMEI and ICEGTC represent a continuum with minor phenotypic and genotypic differences.