Single nucleotide variations in CLCN6 identified in patients with benign partial epilepsies in infancy and/or febrile seizures.

Nucleotide alterations in the gene encoding proline-rich transmembrane protein 2 (PRRT2) have been identified in most patients with benign partial epilepsies in infancy (BPEI)/benign familial infantile epilepsy (BFIE). However, not all patients harbor these PRRT2 mutations, indicating the involvement of genes other than PRRT2. In this study, we performed whole exome sequencing analysis for a large family affected with PRRT2-unrelated BPEI. We identified a non-synonymous single nucleotide variation (SNV) in the voltage-sensitive chloride channel 6 gene (CLCN6). A cohort study of 48 BPEI patients without PRRT2 mutations revealed a different CLCN6 SNV in a patient, his sibling and his father who had a history of febrile seizures (FS) but not BPEI. Another study of 48 patients with FS identified an additional SNV in CLCN6. Chloride channels (CLCs) are involved in a multitude of physiologic processes and some members of the CLC family have been linked to inherited diseases. However, a phenotypic correlation has not been confirmed for CLCN6. Although we could not detect significant biological effects linked to the identified CLCN6 SNVs, further studies should investigate potential CLCN6 variants that may underlie the genetic susceptibility to convulsive disorders.

Efficacy and safety of fosphenytoin for benign convulsions with mild gastroenteritis.

OBJECTIVE: To clarify the efficacy and safety of fosphenytoin for seizures in children with benign convulsions and mild gastroenteritis. METHODS: Using the mailing list of the Annual Zao Conference on Pediatric Neurology, we recruited patients who met the following criteria: (1) clinical diagnosis of benign convulsions with mild gastroenteritis and (2) treatment with intravenous fosphenytoin. Benign convulsions with mild gastroenteritis were defined as a condition of (a) seizures associated with gastroenteritis without electrolyte imbalance, hypoglycemia, or dehydration in patients (b) between 6 months and 3 years of age with (c) no preexisting neurological disorders, (d) no impaired consciousness, and (e) a body temperature less than 38.0 °C before and after the seizures. The efficacy of fosphenytoin was categorized as effective when cessation of seizures was achieved. RESULTS: Data from 16 child patients were obtained (median age, 20 months). Seizures were completely controlled after the initial dose of fosphenytoin in 14 of 16 patients. The median loading dose of fosphenytoin was 22.5 mg/kg. In 10 patients, fosphenytoin was administered after other antiepileptic drugs such as diazepam and midazolam were used. Adverse effects of fosphenytoin, excessive sedation, or intravenous fluid incompatibility were not observed in any patients. CONCLUSION: Fosphenytoin is effective and well tolerated among children with benign convulsions with mild gastroenteritis.

PRRT2 mutation in Japanese children with benign infantile epilepsy.

Mutations in PRRT2 genes have been identified as a major cause of benign infantile epilepsy and/or paroxysmal kinesigenic dyskinesia. We explored mutations in PRRT2 in Japanese patients with BIE as well as its related conditions including convulsion with mild gastroenteritis and benign early infantile epilepsy. We explored PRRT2 mutations in Japanese children who had had unprovoked infantile seizures or convulsion with mild gastroenteritis. The probands included 16 children with benign infantile epilepsy, 6 children with convulsions with mild gastroenteritis, and 2 siblings with benign early infantile epilepsy. In addition, we recruited samples from family members when PRRT2 mutation was identified in the proband. Statistical analyses were performed to identify differences in probands with benign infantile epilepsy according to the presence or absence of PRRT2 mutation. Among a total of 24 probands, PRRT2 mutations was identified only in 6 probands with benign infantile epilepsy. A common insertion mutation, c.649_650insC, was found in 5 families and a novel missense mutation, c.981C>G (I327M), in one. The family history of paroxysmal kinesigenic dyskinesia was more common in probands with PRRT2 mutations than in those without mutations. Our study revealed that PRRT2 mutations are common in Japanese patients with benign infantile epilepsy, especially in patients with a family history of paroxysmal kinesigenic dyskinesia.

Oral mexiletine for lidocaine-responsive neonatal epilepsy.

We report a patient with lidocaine-responsive neonatal epilepsy treated successfully with oral mexiletine. The patient was a male neonate who had seizures since 2days of age. While his seizures were refractory to phenobarbital, lamotrigine, vitamin B6, and midazolam, they were controlled by continuous lidocaine infusion. Oral mexiletine at serum levels of 0.2-0.4µg/ml was used successfully for long-term treatment of his seizures. No delay in psychomotor development was observed at the last follow-up at 20months of age. No mutation was identified in any of four genes: SCN1A, SCN1B, KCNQ2, and KCNQ3. Our patient demonstrates that oral mexiletine can be useful for long-term treatment of patients with lidocaine-responsive epilepsy.

Posterior reversible encephalopathy syndrome associated with IVIG in a patient with Guillain-Barré syndrome.

A 14-year-old girl with Guillain-Barré syndrome manifested headaches during the administration of intravenous immunoglobulin. Magnetic resonance imaging revealed posterior reversible encephalopathy syndrome. Several reports described posterior reversible encephalopathy syndrome associated with intravenous immunoglobulin, but only in adults. We suggest that this syndrome should be considered in children as a neurologic complication.

Genotype and phenotype analyses in 136 patients with single large-scale mitochondrial DNA deletions.

We examined 136 patients with mitochondrial DNA (mtDNA) deletion. Clinical diagnoses included chronic progressive external ophthalmoplegia (94 patients); Kearns-Sayre syndrome (KSS; 33 patients); Pearson's marrow-pancreas syndrome (six patients); and Leigh syndrome, Reye-like syndrome, and mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (one patient). The length and location of deletion were highly variable. Only one patient had deletion within the so-called shorter arc between the two origins of mtDNA replication. The length of deletion and the number of deleted transfer ribonucleic acid (tRNAs) showed a significant relationship with age at onset. Furthermore, KSS patients had longer and larger numbers of deleted tRNAs, which could be risk factors for the systemic involvement of single mtDNA deletion diseases. We found 81 patterns of deletion. Direct repeats of 4 bp or longer flanking the breakpoints were found in 96 patients (70.5%) and those of 10 bp or longer in 49 patients (36.0%). We found two other common deletions besides the most common deletion (34 patients: 25.0%): the 2,310-bp deletion from nt 12113 to nt 14421 (11 patients: 8.0%) and the 7,664-bp deletion from nt 6330 to nt 13993 (ten patients: 7.3%). These deletions had incomplete direct repeats longer than 13 bp with one base mismatch.

Therapeutic efficacy and adverse effects of adrenocorticotropic hormone therapy in west syndrome: differences in dosage of adrenocorticotropic hormone, onset of age, and cause.

OBJECTIVES: To determine the dosage and factors influencing efficacy of adrenocorticotropic hormone (ACTH) for West syndrome. STUDY DESIGN: A retrospective study of 135 patients receiving ACTH therapy with a synthetic analogue for initial effect, seizure outcome 1 year after therapy, and adverse effects. Efficacy and adverse effects were compared among the groups divided by clinical factors: dosage, treatment lag, onset age, and cause. RESULTS: One hundred thirteen patients had seizure control with ACTH. For more than 1 year after ACTH, 59 remained seizure free. Adverse effects were observed in 57, and ACTH therapy was discontinued in 23. The lowest dosage group (0.0125 mg/kg/d) had fewer episodes of discontinuation (P<.05), whereas differences in efficacy between different dosages were insignificant. None of the clinical factors correlated with initial effect. The earlier-onset group (<4 months) showed unfavorable seizure outcome 1 year after ACTH (P<.01). The cryptogenic patients showed better seizure outcome (P<.05) compared with the symptomatic. CONCLUSION: Synthetic ACTH therapy at a lower dosage is as effective as natural ACTH therapy at a higher dosage. Considering the adverse effects and the benefits for seizure control, the ACTH dosage of 0.0125 mg/kg/d (synthetic analogue) is more favorable than larger dosage.

Intravenous lidocaine for status epilepticus during childhood.

The clinical efficacy of lidocaine for convulsive status epilepticus in 53 convulsive episodes was examined in 37 children (17 males, 20 females). Mean age of patients receiving lidocaine was 3 years 7 months (SD 3y 5mo). Lidocaine administration achieved control of status epilepticus in 19 of 53 convulsive episodes (35.8%). Seizures ceased within 5 minutes of lidocaine administration in all 19 patients who were responsive to the drug. Regarding aetiology of status epilepticus and types of seizures, there was no statistical difference in effectiveness. Mild decrease of oxygen saturation, monitored by pulse oximetry, was observed in one patient, which improved by oxygenation using a mask. Lidocaine is a useful anticonvulsive agent; however, the response rate to lidocaine appears to be quite low, as less than half of the seizures were effectively controlled by lidocaine. Favourable properties of the drug include prompt responses, less alteration of consciousness, and fewer adverse effects, including less respiratory depression.

[Choice and administration sequence of antiepileptic agents for status epilepticus and frequent seizures in children].

We investigated the sequence of the administration, the efficacy and the safety of antiepileptic drugs (AED) given intravenously for the treatment of status epilepticus and frequent seizures in children. Our institute has a recommended sequence of AED administration for treatment of status epilepticus: the first-line agent is diazepam (0.3 - 0.5 mg/kg administered intravenously, once or twice). The second-line drugs include midazolam (0.15 - 0.4 mg/kg intravenously, once or twice, and if necessary, followed by continuous infusion at 0.06 - 0.18 mg/kg/hour), lidocaine (1 - 2 mg/kg intravenously, once or twice, and if necessary, followed by continuous infusion at 2 - 4 mg/kg/hour) and phenytoin (10 - 20 mg/kg, infused slowly). For those patients who previously experienced a seizure which was refractory to diazepam but responsive to the second-line agent, it was recommended to use the second-line agent as a first-line agent. When seizures were refractory to the first and second-line agents, thiopental was administered (3 - 10 mg/kg intravenously, and if necessary, followed by continuous infusion at 2 -5 mg/kg/hour). The etiologies of 177 occasions of status epilepticus and frequent seizures were categorized into two groups:epilepsy (n = 95) and situation-related seizures (n = 82). Situation-related seizures included febrile seizures (n = 44), acute encephalopathy/encephalitis (n = 31) and benign infantile convulsions (n = 7). The ages of the patients ranged from 0.1 to 18.4 years (average +/- SD:3.69 +/- 3.15 years). Diazepam was administered as the first-line drug on 157 of 177 occasions (88.7%). On 116 occasions the second-line agents were administered. Midazolam and lidocaine were injected as the second-line agent on 54 (46.6%), and on 33 (28.4%) occasions, respectively, although both midazolam and lidocaine injections were off-label use for seizure control in Japan. Thiopental was used as the third to fifth-line agent. Effective ratios (effective occasions/total occasions) of each drug were the following: thiopental 19/21 (90.4%), midazolam 57/99 (57.6%), lidocaine 25/60 (41.7%), phenytoin 16/41 (39.0%), diazepam 59/164 (36.0%). Thiopental was statistically more effective than midazolam, lidocaine, diazepam or phenytoin (p < 0.01), and midazolam was statistically more effective than diazepam (p < 0.01) or phenytoin (p < 0.05). Administration of thiopental caused complications more frequently than the other agents (p < 0.01): The complications by thiopental were severe in some cases requiring intratracheal intubations and artificial ventilation. From the viewpoint of both efficacy and safety, midazolam should be recommended as one of the first-line agents for status epilepticus.

[Single photon emission computed tomography findings in a case of alternating hemiplegia of childhood in relation to migraine].

Single photon emission computed tomography (SPECT) was performed 3 times during attacks and performed 4 times during postictal periods on a case of alternating hemiplegia of childhood. Hyperperfusion of the corresponding hemisphere to hemiparesis was suggested by asymmetric increase RI uptake during the ictal scans, whereas interictal scans showed symmetric topography of cerebral blood flow. Manifestations except hemiplegia included loss of consciousness and vomiting. These manifestations and ictal SPECT findings are the same evidence as hemiplegic migraine. It suggests that these two disorders have a similar pathophysiology. There are two interesting findings regarding this patient. The first finding is magnetic resonance imaging showed progressive cerebellar atrophy. Second finding is interictal SPECT showed a progressive decrease of cerebral perfusion, especially in cerebellar hemispheres. These two findings suggest alternating hemiplegia of childhood may be a chronic progressive disorder.