GABBR2 mutations determine phenotype in rett syndrome and epileptic encephalopathy.

OBJECTIVE: Rett syndrome (RTT) and epileptic encephalopathy (EE) are devastating neurodevelopmental disorders with distinct diagnostic criteria. However, highly heterogeneous and overlapping clinical features often allocate patients into the boundary of the two conditions, complicating accurate diagnosis and appropriate medical interventions. Therefore, we investigated the specific molecular mechanism that allows an understanding of the pathogenesis and relationship of these two conditions. METHODS: We screened novel genetic factors from 34 RTT-like patients without MECP2 mutations, which account for ∼90% of RTT cases, by whole-exome sequencing. The biological function of the discovered variants was assessed in cell culture and Xenopus tropicalis models. RESULTS: We identified a recurring de novo variant in GABAB receptor R2 (GABBR2) that reduces the receptor function, whereas different GABBR2 variants in EE patients possess a more profound effect in reducing receptor activity and are more responsive to agonist rescue in an animal model. INTERPRETATION: GABBR2 is a genetic factor that determines RTT- or EE-like phenotype expression depending on the variant positions. GABBR2-mediated γ-aminobutyric acid signaling is a crucial factor in determining the severity and nature of neurodevelopmental phenotypes. Ann Neurol 2017;82:466-478.

Painful legs and moving toes syndrome in a 16-year-old girl.

Painful legs and moving toes (PLMT) syndrome is characterized by spontaneous movements of the digits and pain in one or both lower extremities. Of the reported cases, a majority of the patients was female, and the mean age of onset was 58 years. Only one pediatric case has been reported so far. Herein, we report the first adolescent case of PLMT in Korea. A 16-year-old girl complained of tingling pain in the left leg and involuntary movement of the ipsilateral great toe one month after a second untethering surgery. Three years ago, she had undergone untethering surgery to correct lipomeningomyelocele at the S2 level of the conus medullaris. At that time, she was diagnosed with polyradiculopathy at the left L5 level with axonal involvement. We diagnosed her with PLMT syndrome and prescribed gabapentin. Her symptoms diminished within a day. Complete relief from involuntary movement of the toe was achieved within four months. PLMT is a rare syndrome but it should be considered in the differential diagnosis of children and adolescents with limb pain and spontaneous movement in their toes.

Leigh Syndrome in Childhood: Neurologic Progression and Functional Outcome.

BACKGROUND AND PURPOSE: Few studies have analyzed the clinical course and functional outcome in Leigh syndrome (LS). The aim of this study was to determine the clinical, radiological, biochemical, and genetic features of patients with LS, and identify prognostic indicators of the disease progression and neurological outcome. METHODS: Thirty-nine patients who had been diagnosed with LS at the Seoul National University Children's Hospital were included. Their medical records, neuroimaging findings, and histological/biochemical findings of skeletal muscle specimens were reviewed. Targeted sequencing of mitochondrial DNA was performed based on mitochondrial respiratory chain (MRC) enzyme defects. RESULTS: Isolated complex I deficiency was the most frequently observed MRC defect (in 42% of 38 investigated patients). Mitochondrial DNA mutations were identified in 11 patients, of which 81.8% were MT-ND genes. The clinical outcome varied widely, from independent daily activity to severe disability. Poor functional outcomes and neurological deterioration were significantly associated with early onset (before an age of 1 year) and the presence of other lesions additional to basal ganglia involvement in the initial neuroimaging. CONCLUSIONS: The neurological severity and outcome of LS may vary widely and be better than those predicted based on previous studies. We suggest that age at onset and initial neuroimaging findings are prognostic indicators in LS.

Alpha-thalassemia X-linked intellectual disability syndrome identified by whole exome sequencing in two boys with white matter changes and developmental retardation.

Alpha-thalassemia X-linked intellectual disability (ATRX) syndrome is a genetic syndrome caused by mutation of the ATRX gene associated with chromatin remodeling. Recently, a wide spectrum of brain MRI abnormalities and clinical manifestations has been recognized. We describe two male patients with genetically confirmed ATRX syndrome, both presented with developmental delay and white matter changes without typical clinical characteristics of ATRX. Whole-exome sequencing revealed the presence of ATRX mutations: a novel c.6472A>G mutation in Case 1 and a previously reported c.6532C>T mutation in Case 2. These two cases expanded the genetic and clinical spectrum of ATRX syndrome, including brain MRI abnormalities. Our results suggest that male patients with developmental delay and widespread white matter changes, even without distinctive facial dysmorphism and hematologic abnormalities, should be suspected as ATRX syndrome. We support the clinical utility of whole-exome sequencing, particularly in ultra-rare neurological diseases with nonspecific developmental disabilities and atypical presentation.

Noninvasive prenatal diagnosis of duchenne muscular dystrophy: comprehensive genetic diagnosis in carrier, proband, and fetus.

BACKGROUND: Noninvasive prenatal diagnosis of monogenic disorders using maternal plasma and targeted massively parallel sequencing is being investigated actively. We previously demonstrated that comprehensive genetic diagnosis of a Duchenne muscular dystrophy (DMD) patient is feasible using a single targeted sequencing platform. Here we demonstrate the applicability of this approach to carrier detection and noninvasive prenatal diagnosis. METHODS: Custom solution-based target enrichment was designed to cover the entire dystrophin (DMD) gene region. Targeted massively parallel sequencing was performed using genomic DNA from 4 mother and proband pairs to test whether carrier status could be detected reliably. Maternal plasma DNA at varying gestational weeks was collected from the same families and sequenced using the same targeted platform to predict the inheritance of the DMD mutation by their fetus. Overrepresentation of an inherited allele was determined by comparing the allele fraction of 2 phased haplotypes after examining and correcting for the recombination event. RESULTS: The carrier status of deletion/duplication and point mutations was detected reliably through using a single targeted massively parallel sequencing platform. Whether the fetus had inherited the DMD mutation was predicted correctly in all 4 families as early as 6 weeks and 5 days of gestation. In one of these, detection of the recombination event and reconstruction of the phased haplotype produced a correct diagnosis. CONCLUSIONS: Noninvasive prenatal diagnosis of DMD is feasible using a single targeted massively parallel sequencing platform with tiling design.

FOXG1 Mutation is a Low-Incidence Genetic Cause in Atypical Rett Syndrome.

Due to the genetic and clinical heterogeneity of Rett syndrome, patients with nonclassic phenotypes are classified as an atypical Rett syndrome, that is, preserved speech variant, early seizure variant, and congenital variant. Respectively, MECP2, CDKL5, and FOXG1 have been found to be the causative genes, but FOXG1 variants are the rarest and least studied. We performed mutational analyses for FOXG1 on 11 unrelated patients without MECP2 and CDKL5 mutations, who were diagnosed with atypical Rett syndrome. One patient, who suffered from severe early-onset mental retardation and multiple-type intractable seizures, carried a novel, de novo FOXG1 mutation (p.Gln70Pro). This case concurs with previous studies that have reported yields of ∼10%. FOXG1-related atypical Rett syndrome is rare in Korean population, but screening of this gene in patients with severe mental retardation, microcephaly, and early-onset multiple seizure types without specific genetic causes can help broaden the phenotypic spectrum of the distinct FOXG1-related syndrome.

Clinical and mutational spectrum in Korean patients with Rubinstein-Taybi syndrome: the spectrum of brain MRI abnormalities.

OBJECTIVE: Rubinstein-Taybi syndrome (RSTS) is one of the neurodevelopmental disorders caused by mutations of epigenetic genes. The CREBBP gene is the most common causative gene, encoding the CREB-binding protein with histone acetyltransferase (HAT) activity, an epigenetic modulator. To date, there have been few reports on the structural abnormalities of the brain in RSTS patients. In addition, there are no reports on the analysis of CREBBP mutations in Korean RSTS patients. PATIENTS AND METHODS: We performed mutational analyses on 16 unrelated patients with RSTS, with diagnosis based on the typical clinical features. Their medical records and brain MRI images were reviewed retrospectively. RESULTS: Ten of 16 patients (62.5%) had mutations in the CREBBP gene. The mutations included five frameshift mutations (31.2%), two nonsense mutations (12.5%), and three multiexon deletions (18.8%). There were no remarkable significant differences in the clinical features between those with and without a CREBBP mutation, although brain MRI abnormalities were more frequently observed in those with a CREBBP mutation. Seven of 10 patients in whom brain imaging was performed had structural abnormalities, including Chiari malformation type 1, thinning of the corpus callosum, and delayed myelination. There were no differences in delayed development or cognitive impairment between those with and without abnormal brain images, while epilepsy was involved in two patients who had abnormalities on brain MRI images. CONCLUSIONS: We investigated the spectrum of CREBBP mutations in Korean patients with RSTS for the first time. Eight novel mutations extended the genetic spectrum of CREBBP mutations in RSTS patients. This is also the first study showing the prevalence and spectrum of abnormalities on brain MRI in RSTS patients.

Epilepsy phenotype associated with a chromosome 2q24.3 deletion involving SCN1A: Migrating partial seizures of infancy or atypical Dravet syndrome?

The deletion of a sodium channel gene cluster located on chromosome 2q24.3 is associated with variable epilepsy phenotypes, including Dravet syndrome and migrating partial seizures of infancy. Although SCN1A is considered as the major contributor to the epilepsy phenotype, the role of other sodium channel genes that map within this cluster has not been delineated. We presented five new cases with a chromosome 2q24.3 deletion involving SCN1A and investigated their epilepsy phenotype in relation to the extent of the deletion. Three cases with deletion of the whole sodium channel gene cluster (SCN3A, SCN2A, SCN1A, SCN9A, and SCN7A) exhibited a complex epilepsy phenotype that was atypical for Dravet syndrome and suggestive of migrating partial seizures of infancy: early seizure onset (before 2 months of age), severe developmental delay from seizure onset, multifocal interictal spikes, polymorphous focal seizures, and acquired microcephaly. Two cases with partial deletion of SCN1A and SCN9A and whole SCN1A deletion had an epilepsy phenotype of Dravet syndrome. A literature review of cases with chromosome 2q24.3 deletion revealed that, in most Dravet syndrome cases, it does not involve SCN2A and SCN3A, whereas a complex epilepsy phenotype that is shared with migrating partial seizures of infancy was associated with cases of deletion of the whole sodium channel gene cluster.

Menkes disease in Korea: ATP7A mutation and epilepsy phenotype.

OBJECTIVE: Menkes disease (MD) is an X-linked recessive disorder characterized by progressive neuro-degeneration. There are few reports of epilepsy and electroencephalography (EEG) findings and few reports of MD patients in Korea. We explored MD genotypes and phenotypes, including epilepsy, in Korean patients. PATIENTS AND METHODS: All patients diagnosed as MD in our hospital, seven males, were included in this study. Their medical records and EEG findings were reviewed retrospectively. RESULTS: All male patients had developmental delay/regression with hypotonia, and the appearance of their hair and skin was characteristic of MD. A recurrent missense mutation was found in two patients. Two nonsense mutations and one gross deletion were also found. The five male patients with identified molecular defects experienced anticonvulsant-resistant seizures. EEGs in focal seizures usually revealed interictal focal epileptiform discharges over the posterior region without focal slowing. This was followed by modified hypsarrhythmia with less polymorphic background activity in spasms and anteriorly dominant diffuse slowing with generalized and multifocal epileptiform discharges in myoclonic or generalized tonic seizures. Two patients with the same G727R missense mutation both developed seizures that evolved with age but differed in severity. CONCLUSIONS: G727R missense mutation may be relatively common in Korea, as in other countries. There was no clear correlation of genotype with phenotype, even in epilepsy and EEG abnormalities.

Rare coincidence of familial central core disease and hemophagocytic lymphohistiocytosis.

Central core disease is a congenital myopathy caused by mutations in RYR1. A 6-year-old girl was admitted due to difficulty in running and climbing stairs. Another 13 members through the four generations had similar symptoms, indicating autosomal dominant inheritance. Muscle biopsy showed the characteristic central cores in predominant type 1 fibers. She later developed hemophagocytic lymphohistiocytosis. Mutation analysis identified c.14582G>A in RYR1, and c.1693delG and c.2954 + 5G>A in UNC13D. To our knowledge, this is the first case of a patient with central core disease, carrying a RYR1 mutation in a Korean large family, who had concurrent familial hemophagocytic lymphohistiocytosis.

Mutational analysis of paediatric patients with tuberous sclerosis complex in Korea: genotype and epilepsy.

To date, only a few studies have reported that, in tuberous sclerosis, TSC2 mutations are more frequently associated with infantile spasms and cognitive impairment compared to TSC1 mutations. We analyzed the mutational spectrum of patients with tuberous sclerosis in Korea and attempted to explore the associations between genotype and seizure type/outcome. We performed mutational analyses on 70 unrelated patients with clinically confirmed tuberous sclerosis by using direct DNA sequencing and/or multiplex ligation-dependent probe amplification. The patients' medical records, including epilepsy type and outcome, were reviewed retrospectively. We identified pathogenic mutations in 55 patients (79%), 25 of which were novel. There were 12 TSC1 mutations and 43 TSC2 mutations. TSC1 mutations included 8 frameshift and 4 nonsense mutations. TSC2 mutations included 12 frameshift, 10 nonsense, 6 splicing, and 6 missense mutations, as well as 4 in-frame deletions and 5 large deletions. Fifty-eight patients had epilepsy (83%), including 19 patients with a history of infantile spasms. Compared to patients with TSC1 mutations, individuals with TSC2 mutations had a significantly higher frequency of epilepsy (p<0.05) and tended to have a higher frequency of infantile spasms (37% vs 17%; p<0.3). Most of the patients with TSC2 mutations who developed infantile spasms exhibited subsequent epilepsy (13/14; 93%). However, the presence/absence of infantile spasms did not influence seizure remission or cognitive outcome.

Effectiveness of intravenous levetiracetam as an adjunctive treatment in pediatric refractory status epilepticus.

OBJECTIVES: Intravenous levetiracetam (LEV) has been shown to be effective and safe in treating adults with refractory status epilepticus (SE). We sought to investigate the efficacy and safety of intravenous LEV for pediatric patients with refractory SE. METHODS: We performed a retrospective medical-record review of pediatric patients who were treated with intravenous LEV for refractory SE. Clinical information regarding age, sex, seizure type, and underlying neurological status was collected. We evaluated other anticonvulsants that were used prior to administration of intravenous LEV and assessed loading dose, response to treatment, and any adverse events from intravenous LEV administration. RESULTS: Fourteen patients (8 boys and 6 girls) received intravenous LEV for the treatment of refractory SE. The mean age of the patients was 4.4 ± 5.5 years (range, 4 days to 14.6 years). Ten of the patients were neurologically healthy prior to the refractory SE, and the other 4 had been previously diagnosed with epilepsy. The mean loading dose of intravenous LEV was 26 ± 4.6 mg/kg (range, 20-30 mg/kg). Seizure termination occurred in 6 (43%) of the 14 patients. In particular, 4 (57%) of the 7 patients younger than 2 years showed seizure termination. No immediate adverse events occurred during or after infusions. CONCLUSIONS: The current study demonstrated that the adjunctive use of intravenous LEV was effective and well tolerated in pediatric patients with refractory SE, even in patients younger than 2 years. Intravenous LEV should be considered as an effective and safe treatment option for refractory SE in pediatric patients.

Hoyeraal-Hreidarsson syndrome with a DKC1 mutation identified by whole-exome sequencing.

BACKGROUND: Hoyeraal-Hreidarsson syndrome is a severe multisystem disorder that is characterized by bone-marrow failure, intrauterine growth retardation, microcephaly, immunodeficiency, and cerebellar atrophy. This rare disease shares clinical features with dyskeratosis congenita and, together, they are recognized as a group of disorders caused by telomere dysfunction. As the genetic background of dyskeratosis congenita or Hoyeraal-Hreidarsson syndrome has expanded rapidly, multiple causative genes and inheritance patterns pose a great challenge to their genetic diagnosis. CASE PRESENTATION: A 3-month-old boy was referred for head titubation and tremulous movements of the trunk. Multiple petechiae also developed on his face and trunk at the age of 5 months. Extensive evaluation, including brain magnetic resonance imaging, hematologic tests, and bone-marrow evaluation, revealed cerebellar atrophy and aplastic anemia. His elder brother exhibited a similar clinical presentation and died from sepsis after hematopoietic stem cell transplantation. Although skin pigmentation or nail dystrophy was not evident, Hoyeraal-Hreidarsson syndrome was suggested as a differential diagnosis. Instead of the conventional gene-specific approach with Sanger sequencing, we used whole-exome sequencing for the genetic diagnosis of this patient with possible Hoyeraal-Hreidarsson syndrome and successfully identified a missense mutation (c.146C>T, p.Thr49Me) in DKC1. CONCLUSION: This case suggests that whole-exome sequencing is particularly useful for the genetic diagnosis of extremely rare diseases with genetic heterogeneity, although there are many limitations, including cost and uneven or suboptimal coverage, to the application of this method as a routine genetic diagnosis.

Electroencephalography in pediatric moyamoya disease: reappraisal of clinical value.

PURPOSE: The clinical value of electroencephalography (EEG) in pediatric moyamoya disease has been underestimated, though the characteristic patterns are well known. We undertook this study to evaluate the clinical value of EEG as a diagnostic and postoperative follow-up modality in pediatric moyamoya disease. METHODS: We retrospectively reviewed the pre and postoperative EEG with effective hyperventilation in 127 pediatric moyamoya patients and compared their patterns with hemodynamic images. RESULTS: One hundred and two patients (80.3 %) among 127 showed abnormal EEG findings before revascularization surgery. The typical rebuild-up phenomenon was observed in 82 (64.6 %) and localized build-up in 32 (25.2 %) without any significant clinical ischemic events during and after hyperventilation. The rebuild-up was observed more frequently in younger age groups (less than 13 years) and Suzuki stages III. The location of the rebuild-up distribution and asymmetric build-up was consistent with the area showing hemodynamic abnormalities on single photon emission computed tomography and/or perfusion magnetic resonance imaging. Postoperative follow-up EEGs were performed in 41 patients. Six patients with remaining rebuild-up in postoperative follow-up EEG showed poorer postoperative clinical outcomes. CONCLUSIONS: This study may reappraise EEG as an easy, safe, and adjunctive diagnostic and postoperative follow-up modality for evaluation of hemodynamic status and clinical outcome, especially in children with moyamoya disease.

Lacosamide as an adjunctive therapy in pediatric patients with refractory focal epilepsy.

PURPOSE: To evaluate the efficacy and safety of lacosamide in pediatric patients with refractory focal epilepsy. METHODS: We reviewed retrospectively the medical records of children younger than 18 years of age treated at Seoul National University Bundang Hospital, in whom oral lacosamide was used as an adjunctive treatment for refractory focal epilepsy. Clinical information regarding the patients' epilepsy and the outcome of lacosamide treatment was gathered and analyzed. RESULTS: Twenty-one patients (16 boys, 5 girls) were included, with a median age of 13.9 (range, 1.2-17.9) years. The mean number of concomitant antiepileptic drugs was 3.0 (range, 1-6) and the mean duration of follow-up was 10.1 (range, 6.1-13.0) months. The mean maintenance dose of lacosamide was 5.4 (range, 1.4-9.8) mg/kg/day. Fourteen patients (67%) were responders; four of these were seizure free at the last follow-up. Seven patients (33%) were nonresponders: two of these presented with <50% seizure reduction and five showed no change in seizure frequency. Two patients (10%) discontinued oral lacosamide because of adverse events (aggressive behavior and depression). Mild transient treatment-related adverse events were observed in eight of the 21 patients (38%). CONCLUSIONS: Lacosamide represents a useful drug that is effective for a wide range of pediatric refractory focal epilepsy and is well tolerated.

A unique phenotype of 2q24.3-2q32.1 duplication: early infantile epileptic encephalopathy without mesomelic dysplasia.

The voltage-gated sodium channel genes and HOXD genes are clustered on chromosome 2q, and duplication of this region is associated with 2 clinical phenotypes: early-onset epilepsy and mesomelic dysplasia Kantaputra type, respectively. We report a case involving 2q24.3-2q32.1 duplication encompassing both the voltage-gated sodium channel and HOXD gene clusters, which were detected by a comparative genomic hybridization array. The associated clinical features were early-infantile-onset epilepsy, hypoplastic left heart syndrome, and global developmental delay. However, no features of mesomelic dysplasia were found. A fluorescent in situ hybridization study showed that the noncontiguous insertion of the duplicated chromosome 2q segment into chromosome 6q was inherited from the father, who has a balanced insertional translocation. The unique genotype-phenotype correlation in the present case suggests that dosage-sensitive effects might apply only to the voltage-gated sodium channel genes.

Involuntary movement in pediatric moyamoya disease patients: consideration of pathogenetic mechanism using neuroimaging studies.

PURPOSE: Involuntary movement is a rare symptom of moyamoya disease (MMD). No consensus has been reached regarding its clinical features and pathogenetic mechanism. Therefore, pediatric MMD patients presenting with involuntary movement were retrospectively analyzed, focusing on the image findings. METHODS: A total of 513 patients who were treated for MMD were reviewed. After exclusion of MMD syndromes and those with accompanying conditions related to involuntary movements, five patients (mean age: 11.6 years, range: 5-13 years) were evaluated. RESULTS: All of the patients improved their symptoms rapidly after the indirect bypass operations to the contralateral hemisphere. All remained symptom-free during the long follow-up period. Comprehensive evaluation of the preoperative imaging findings failed to suggest a characteristic feature in common, corresponding to the existing hypotheses or a new hypothesis. Only one patient showed infarction preoperatively, and only one patient showed prominently enhanced collateral vessels in the basal ganglia. Although a decrease in vascular reserve was observed in all patients, the location and laterality were nonspecific. CONCLUSION: There still appears to be confusion regarding the pathogenetic mechanism of involuntary movement in MMD with no repetitive, established imaging features to explain the phenomenon. Nonetheless, with its excellent response to surgical treatment, clinical awareness of this rare symptom of MMD should be emphasized as a differential diagnosis for secondary movement disorder in children.

Screening Autoimmune Anti-neuronal Antibodies in Pediatric Patients with Suspected Autoimmune Encephalitis.

BACKGROUND AND PURPOSE: The aim of this study was to identify and describe the pediatric autoimmune encephalitis cases positive for anti-neuronal antibody tests. METHODS: Screening of six anti-neuronal antibodies in 23 children with suspected autoimmune encephalitis was performed by cell-based indirect immunofluorescence test with patients' serum or cerebrospinal fluid. RESULTS: Among the 23 cases enrolled here, eight patients (35%) were positive for the anti-N-methyl-d-aspartate (NMDA) receptor antibody and one patient (4%) was positive for the anti-contactin-associated protein-like 2 (CASPR2) antibody. In the anti-NMDA receptor antibody-positive group, seizure and movement disorders were the most prominent features and were present in all patients. A tumor was present in only one patient. Three patients with infant- and toddler-onset disease did not exhibit a classic multistage illness. In addition to seizure and dyskinesia, aphasia or mutism without severe consciousness impairment was present in all three patients. These atypical clinical presentations may suggest different pathomechanism of anti-NMDA receptor encephalitis among these age groups. The patient who was positive for the anti-CASPR2 antibody was an 8-year-old girl who presented with fever, encephalopathy, and seizure. Neuromyotonia or other dyskinesia was not present. CONCLUSIONS: Eight anti-NMDA receptor antibody positive patients and one CASPR2 positive patient were identified from the screening of six anti-neuronal antibodies in pediatric patients suspected with autoimmune encephalitis. Developmental regression specifically for language skills was suggested as one of the atypical clinical features in infants and toddler onset anti-NMDA receptor antibody positive patients.

Clinical and EEG risk factors for subsequent epilepsy in patients with complex febrile seizures.

PURPOSE: To identify the risk factors for subsequent epilepsy in patients with complex febrile seizures from a single-center retrospective cohort. METHODS: The medical records of 1091 patients discharged with a diagnosis of febrile seizures from the Seoul National University Bundang Hospital from February 2004 to October 2009 were reviewed. One hundred eighty-three patients (107 boys and 76 girls) with complex febrile seizures who showed normal neurocognitive development were included in the analysis. Clinical characteristics, including features of complex febrile seizure, initial interictal electroencephalographic findings, and subsequent epilepsy, were reviewed and the odds ratio of subsequent epilepsy was estimated. The mean follow-up duration for subsequent epilepsy was 6.1 years (range, 2.5-8.0 years). RESULTS: Complex febrile seizures were observed in 22.6% of all patients with febrile seizures. Among 183 patients with complex febrile seizures, 22 patients (12.0%) developed subsequent epilepsy. Prolonged (>10 min) seizure (p=0.031; odds ratio, 3.04; 95% confidence interval, 1.11-8.32) or the presence of multiple seizures for 24 h (p=0.032; odds ratio, 3.63; 95% confidence interval, 1.12-11.8) was significantly more frequent in patients with subsequent epilepsy, whereas the presence of focal seizure was not significantly different. Epileptiform discharges (focal in all cases) were significantly more frequent in patients with subsequent epilepsy (50% vs. 13%, p=0.002), with an odds ratio of 5.15 (95% confidence interval, 1.84-14.5). CONCLUSION: The presence of epileptiform discharges is a significant risk factor for subsequent epilepsy in patients with complex febrile seizures. Electroencephalography should be considered in all patients with complex febrile seizures especially those who had multiple or prolonged seizures.

Molecular diagnosis of congenital muscular dystrophies with defective glycosylation of alpha-dystroglycan using next-generation sequencing technology.

Targeted resequencing using next-generation sequencing technology is being rapidly applied to the molecular diagnosis of human genetic diseases. The group of muscular dystrophies may be an appropriate candidate for this approach because these diseases exhibit genotype-phenotype heterogeneity. To perform a proof-of-concept study, we selected four patients with congenital muscular dystrophies with defective glycosylation of alpha-dystroglycan. A custom-solution-based target enrichment kit was designed to capture whole-genic regions of the 26 muscular-dystrophy-related genes, including six genes implicated in alpha-dystroglycanopathies. Although approximately 95% of both coding and noncoding regions were covered with at least 15-read depth, parts of the coding exons of FKRP and POMT2 were insufficiently covered. Homozygous and compound heterozygous POMGnT1 mutations were found in two patients. Two novel noncoding variants of FKTN were identified in one patient who had a retrotransposon insertion mutation of FKTN in only one allele. The current targeted resequencing strategy yielded promising results for the extension of this method to other muscular dystrophies. As suboptimal coverage in a small subset of coding regions may affect the sensitivity of the method, complementary Sanger sequencing may be required.