[Clinical characteristics of early juvenile GM2 gangliosidosis: a case report].

We describe the case of a 15-year-old male with early juvenile type GM2 gangliosidosis. He first manifested with progressive clumsiness in his extremities at the age of 1.5 years, followed by motor regression. Intellectual disability became evident as late as age 6 years. This discrepancy along with rapid motor deterioration after varicella infection, lack of startle response or macrocephaly, and paucity of myoclonus were thought to be characteristic of juvenile GM2 gangliosidosis. In contrast to the cerebellar atrophy as the initial finding in usual juvenile GM2 gangliosidosis, magnetic resonance imaging revealed initially cerebral, and subsequently cerebellar, progressive atrophy. Autistic behavioral problems, including phonophobia, during intellectual regression in this patient was also unusual in juvenile GM2 gangliosidosis. Thus, recognition of these features would prompt proper diagnosis and insights into the pathomechanisms of GM2 gangliosidosis.

Phenotypic variability in childhood of skeletal muscle sodium channelopathies.

BACKGROUND: Mutations of the SCN4A gene cause several skeletal muscle channelopathies and overlapping forms of these disorders. However, the variability of the clinical presentation in childhood is confusing and not fully understood among pediatric neurologists. PATIENTS: We found three different mutations (p.V445M, p.I693L, and a novel mutation, p.V1149L) in SCN4A but not in the CLCN1 gene. The patient with p.V445M showed the clinical phenotype of sodium channel myotonia, but her clear symptoms did not appear until 11 years of age. Her younger sister and mother, who have the same mutation, displayed marked intrafamilial phenotypic heterogeneity from mild to severe painful myotonia with persistent weakness. The patient with p.I693L exhibited various symptoms that evolved with age, including apneic episodes, tonic muscular contractions during sleep, fluctuating severe episodic myotonia, and finally episodic paralyses. The patient with the novel p.V1149L mutation exhibited episodic paralyses starting at 3 years of age, and myotonic discharges were detected at 11 years of age for the first time. CONCLUSION: The present cohort reveals the complexity, variability, and overlapping nature of the clinical features of skeletal muscle sodium channelopathies. These are basically treatable disorders, so it is essential to consider genetic testing before the full development of a patient's condition.

Prevalence of childhood epilepsy and distribution of epileptic syndromes: a population-based survey in Okayama, Japan.

PURPOSE: A population-based survey childhood epilepsy was undertaken in Okayama Prefecture, Japan, to determine the prevalence rate and the distribution of epilepsies and epileptic syndromes according to the International Classification (ILAE, 1989). METHODS: Information on patients younger than 13 years with active epilepsy was collected from medical records. Patients diagnosed with epilepsy according to clinical and EEG findings were put on the list even if those patients had had a single seizure or seizures occurring during febrile episodes. RESULTS: In total, 2,220 cases were identified from a background population of 250,997. The prevalence rate was 8.8 per 1,000. If we exclude patients who had experienced a single seizure or seizures occurring during febrile episodes to compare our results with previous reports, the prevalence rate was 5.3 per 1,000. Of the 2,220 cases, 2,030 (91.4%) were classified into three major categories by ILAE classification. They consisted of 1,556 (76.7%) with localization-related epilepsy, 453 (22.3%) with generalized epilepsy, and 21 (1.0%) with undetermined epilepsy. Of the 2,030 cases, 309 (15.2%) were classified into epileptic syndrome categories, and 84.8% of the total were nonspecific types of epilepsy. CONCLUSIONS: The prevalence rate of childhood epilepsy was distributed from 5.3 to 8.8 per 1,000. The appearance rate of various types of epileptic syndromes was low. Most cases could not be classified into the detailed categories of the International Classification (ILAE, 1989).

Initiation of treatment and selection of antiepileptic drugs in childhood epilepsy.

PURPOSE: A retrospective study was carried out on 53 cases with childhood epilepsy to evaluate the validity of the initial selection of antiepileptic drug (AED). METHODS: We investigated the AEDs selected at the beginning of the treatment from the medical records of 53 untreated cases. A follow-up study was undertaken to evaluate the effects of the AEDs. In the second study, we investigated the AEDs of 10 cases with atypical benign partial epilepsy (ABPE), to clarify whether the initial AEDs selected for rolandic epilepsy were related to the appearance of ABPE. RESULTS: The AEDs used at the initial stage consisted of carbamazepine (CBZ), valproic acid (VPA), phenobarbital (PB), and vitamin B6. The main AEDs were CBZ and VPA for localization-related epilepsy, and VPA for generalized epilepsy. The initial selection of AEDs in 41 (85.4%) of 48 cases treated with AEDs were considered to be correct from the results of follow-up. We could not specify any AEDs that related to the appearance of ABPE. CONCLUSIONS: The selection of AED in this series was considered to be most appropriate. We proposed a criterion to determine whether to begin the AED treatment immediately at the initial seizure.