Tsukasa Ohashi

Genotype–phenotype correlations in alternating hemiplegia of childhood

Objective: Clinical severity of alternating hemiplegia of childhood (AHC) is extremely variable. To investigate genotype–phenotype correlations in AHC, we analyzed the clinical information and ATP1A3 mutations in patients with AHC. Methods: Thirty-five Japanese patients who were clinically diagnosed with AHC participated in this study. ATP1A3 mutations were analyzed using Sanger sequencing. Detailed clinical information was collected from family members of patients with AHC and clinicians responsible for their care. Results: Gene analysis revealed 33 patients with de novo heterozygous missense mutations of ATP1A3: Glu815Lys in 12 cases (36%), Asp801Asn in 10 cases (30%), and other missense mutations in 11 cases. Clinical information was compared among the Glu815Lys, Asp801Asn, and other mutation groups. Statistical analysis revealed significant differences in the history of neonatal onset, gross motor level, status epilepticus, and respiratory paralysis in the Glu815Lys group compared with the other groups. In addition, 8 patients who did not receive flunarizine had severe motor deteriorations. Conclusions: The Glu815Lys genotype appears to be associated with the most severe AHC phenotype. Although AHC is not generally seen as a progressive disorder, it should be considered a disorder that deteriorates abruptly or in a stepwise fashion, particularly in patients with the Glu815Lys mutation.

West syndrome associated with mosaic duplication of FOXG1 in a patient with maternal uniparental disomy of chromosome 14

FOXG1 on chromosome 14 has recently been suggested as a dosage‐sensitive gene. Duplication of this gene could cause severe epilepsy and developmental delay, including infantile spasms. Here, we report on a female patient diagnosed with maternal uniparental disomy of chromosome 14 and West syndrome who carried a small supernumerary marker chromosome. A chromosomal analysis revealed mosaicism of 47,XX, + mar[8]/46,XX[18]. Spectral karyotyping multicolor fluorescence in situ hybridization analysis confirmed that the marker chromosome was derived from chromosome 14. A DNA methylation test at MEG3 in 14q32.2 and microsatellite analysis using polymorphic markers on chromosome 14 confirmed that the patient had maternal uniparental disomy 14 as well as a mosaic small marker chromosome of paternal origin containing the proximal long arm of chromosome 14. Microarray‐based comparative genomic hybridization analysis conclusively defined the region of the gain of genomic copy numbers at 14q11.2‐q12, encompassing FOXG1. The results of the analyses of our patient provide further evidence that not only duplication but also a small increase in the dosage of FOXG1 could cause infantile spasms.

High prevalence of genetic alterations in early-onset epileptic encephalopathies associated with infantile movement disorders.

OBJECTIVE Recent studies have elucidated causative roles for genetic abnormalities in early-onset epileptic encephalopathies (EOEE). Accompanying characteristic features, in addition to seizures, have also been suggested to provide important clues for an early and accurate genetic diagnosis of affected patients. In this study, we investigated the underlying genetic causes in patients with EOEE associated with infantile movement disorders. METHODS We examined 11 patients with EOEE and involuntary movements (nine with West syndrome and two with nonsyndromic epileptic encephalopathy). All showed severe developmental delay, cognitive impairment, and involuntary movements such as chorea, ballism, dyskinesia or myoclonus, and hand stereotypies. We performed whole-exome sequencing of 10 patients, while the other patient underwent high-resolution melting analysis of candidate EOEE genes. RESULTS We identified mutations in CDKL5, SCN2A, SETD5, ALG13, and TBL1XR1 in seven patients with West syndrome, and in SCN1A and GRIN1 in the two patients with unclassified epileptic encephalopathy. All mutations were validated as de novo events. The genetic cause was undetermined in the remaining two patients. CONCLUSIONS We found pathogenic mutations in seven genes, in nine of 11 patients with EOEE and involuntary movements. Although the results of our study are preliminary because of the small number of patients, they nevertheless suggest that specific accompanying phenotypes such as hyperkinetic movements or hand stereotypies could be important in narrowing the disease spectrum and identifying causative genetic abnormalities.

Dandy–Walker malformation associated with heterozygous ZIC1 and ZIC4 deletion: Report of a new patient†

We report on a female patient with Dandy–Walker malformation possibly caused by heterozygous loss of ZIC1 and ZIC4. The patient presented with mental retardation, epilepsy, and multiple congenital malformations including spina bifida, mild dysmorphic facial features including, thick eyebrows, broad nose, full lips, macroglossia, and hypoplasia of the cerebellar vermis with enlargement of the fourth ventricle on brain magnetic resonance imaging, which is consistent with Dandy–Walker malformation. A chromosome analysis showed interstitial deletion of chromosome 3q23‐q25.1. Fluorescence in situ hybridization (FISH) and microarray‐based genomic analysis revealed the heterozygous deletion of ZIC1 and ZIC4 loci on 3q24. Her facial features were not consistent with those observed in blepharophimosis–ptosis–epicanthus inversus syndrome (BPES) involving FOXL2 abnormality. Other deleted genes at 3q23‐25.1 might contribute to the dysmorphic facial appearance. A milder phenotype as the Dandy–Walker malformation in our patient supports the idea that modifying loci/genes can influence the development of cerebellar malformation.

Infantile epileptic encephalopathy with a hyperkinetic movement disorder and hand stereotypies associated with a novel SCN1A mutation

We report a female patient who presented with intractable epileptic seizures, profound developmental delay since early infancy, and hyperkinetic movements with hand stereotypies. The patient initially developed focal seizures with multiple foci at 3 months of age. Thereafter, the seizures evolved to frequent episodes of hyperthermia-induced status epilepticus. A novel de novo SCN1A mutation was identified by whole-exome sequence analysis. This case demonstrates that SCN1A mutations may cause movement disorders as an atypical phenotype and the case history of this patient may expand our understanding of the clinical spectrum of SCN1A-associated epileptic encephalopathy. [Published with video sequences].

Congenital variant of Rett syndrome due to an intragenic large deletion in MECP2

Rett syndrome (RTT) is a neurodevelopmental disorder that is one of the most common causes of mental retardation in females. RTT diagnosis is based on distinct clinical criteria. We describe here a female patient with severe phenotype of congenital variant RTT. The patient originally presented with severe developmental delay prior to the age of 6 months and later exhibited characteristic features of RTT that included air swallowing, bruxism, and hand stereotypies. Results of an array-based comparative genomic hybridization analysis indicated there was a very small microdeletion in Xq28. Multiplex ligation-dependent probe amplification analysis further confirmed there were heterozygous deletions of intron 2, exon 3, intron 3, and part of exon 4 in MECP2. Findings in the present patient confirm the view that large MECP2 deletions are an important cause of severe congenital variant RTT. To ensure an accurate diagnosis of congenital variant RTT, a multiplex ligation-dependent probe amplification analysis of MECP2 should be performed in patients suspected of having this disorder.

A 7q31.33q32.1 microdeletion including LRRC4 and GRM8 is associated with severe intellectual disability and characteristics of autism

A 4-year-old boy with severe intellectual disability (ID) and characteristics of autism was found to have a de novo 1.9-Mb microdeletion in 7q31.33q32.1, in which LRRC4, GRM8, and 11 other genes were included. GRM8 is associated with attention deficit hyperactivity disorder. LRRC4 is related to synaptic cell adhesion molecules, some of which are associated with autism. The deletion of LRRC4 may be responsible for the severe ID and characteristics of autism observed in the present patient.

Acquired Opercular Epilepsy With Oromotor Dysfunction: Magnetoencephalographic Analysis and Efficacy of Corticosteroid Therapy

The authors describe herein the magnetoencephalographic findings and long-term outcome of a girl with acquired opercular epilepsy with oromotor dysfunction. She presented with brief episodes of unconsciousness, tremulous movements of the upper limbs, and negative myoclonus, in addition to convulsive seizures. She also had prolonged episodes of dysarthria and oral motor dysfunction, a gradual decrease in speech output, impairment of finger movements, and deterioration in cognitive performance over several years. Her electroencephalography (EEG) recordings showed notable continuous sharp or sharp-slow discharges during sleep. Brain magnetic resonance images revealed no structural anomalies. Magnetoencephalographic analysis showed broadly distributed epileptic foci around the sylvian fissure, including a secondary source, explaining the specific prolonged neurological dysfunction. Antiepileptic drugs could control her seizures; however, they did not improve the other neurological symptoms or epileptiform discharge on EEG. Administration of low-dose prednisolone over a long period was effective for improving the neurological impairments of this patient.

Early-onset absence epilepsy at eight months of age

Early-onset absence epilepsy refers to patients with absence seizures beginning before age four and comprises a heterogeneous group of epilepsies. Onset of absence seizures in the first year of life is very rare. We report a girl with intractable absence seizures with onset at age eight months. Her seizures were characterised by loss of responsiveness, with eyes drifting upwards and some myoclonic jerks of the upper and lower limbs. These symptoms were accompanied by bilaterally symmetric high-amplitude 2–2.5 Hz generalised spike-and-wave discharges on the electroencephalogram. Her seizures were refractory to conventional antiepileptic drugs; treatment with adrenocorticotropic hormone was transiently effective. Comprehensive metabolic screening, cytogenetic, and genetic analysis did not determine an underlying cause of her condition. Patients with intractable, very early-onset absence epilepsy with a myoclonic component have an unfavourable outcome and may be classified under a new epileptic syndrome, such as “early infantile absence epilepsy”.

Neuropsychiatric Disorder Associated with Group G Streptococcus Infection

Immune-mediated central nervous system manifestations of group A β-hemolytic Streptococcus (GABHS) infection include Sydenhams chorea, pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS)—which includes tic and obsessive compulsive disorders—and a variety of neurobehavioral disorders. We report a case of Streptococcus dysgalactiae subspecies equisimilis (group G Streptococcus) (GGS) infection associated with involuntary movements, complex tics, and emotional lability in an 11-year-old Japanese girl. Serum IgM and IgG antibodies to lysoganglioside were positive, and she responded rapidly to intravenous immunoglobulin treatment. Neuropsychiatric disorder associated with GGS infection was ultimately diagnosed. The present findings suggest that neuropsychiatric disorders can result from GGS infection and that the pathogenic mechanism is similar to that of GABHS infection. Future large-scale studies should examine the relation between GGS infection and onset of neuropsychiatric disorder.