Genetic testing in benign familial epilepsies of the first year of life: clinical and diagnostic significance.

PURPOSE: To dissect the genetics of benign familial epilepsies of the first year of life and to assess the extent of the genetic overlap between benign familial neonatal seizures (BFNS), benign familial neonatal-infantile seizures (BFNIS), and benign familial infantile seizures (BFIS). METHODS: Families with at least two first-degree relatives affected by focal seizures starting within the first year of life and normal development before seizure onset were included. Families were classified as BFNS when all family members experienced neonatal seizures, BFNIS when the onset of seizures in family members was between 1 and 4 months of age or showed both neonatal and infantile seizures, and BFIS when the onset of seizures was after 4 months of age in all family members. SCN2A, KCNQ2, KCNQ3, PPRT2 point mutations were analyzed by direct sequencing of amplified genomic DNA. Genomic deletions involving KCNQ2 and KCNQ3 were analyzed by multiple-dependent probe amplification method. KEY FINDINGS: A total of 46 families including 165 affected members were collected. Eight families were classified as BFNS, 9 as BFNIS, and 29 as BFIS. Genetic analysis led to the identification of 41 mutations, 14 affecting KCNQ2, 1 affecting KCNQ3, 5 affecting SCN2A, and 21 affecting PRRT2. The detection rate of mutations in the entire cohort was 89%. In BFNS, mutations specifically involve KCNQ2. In BFNIS two genes are involved (KCNQ2, six families; SCN2A, two families). BFIS families are the most genetically heterogeneous, with all four genes involved, although about 70% of them carry a PRRT2 mutation. SIGNIFICANCE: Our data highlight the important role of KCNQ2 in the entire spectrum of disorders, although progressively decreasing as the age of onset advances. The occurrence of afebrile seizures during follow-up is associated with KCNQ2 mutations and may represent a predictive factor. In addition, we showed that KCNQ3 mutations might be also involved in families with infantile seizures. Taken together our data indicate an important role of K-channel genes beyond the typical neonatal epilepsies. The identification of a novel SCN2A mutation in a family with infantile seizures with onset between 6 and 8 months provides further confirmation that this gene is not specifically associated with BFNIS and is also involved in families with a delayed age of onset. Our data indicate that PRRT2 mutations are clustered in families with BFIS. Paroxysmal kinesigenic dyskinesia emerges as a distinctive feature of PRRT2 families, although uncommon in our series. We showed that the age of onset of seizures is significantly correlated with underlying genetics, as about 90% of the typical BFNS families are linked to KCNQ2 compared to only 3% of the BFIS families, for which PRRT2 represents the major gene.

Personality profile and health-related quality of life in adults with previous continuous spike-waves during slow sleep syndrome.

INTRODUCTION: Epilepsy with continuous spike-waves during slow sleep syndrome (CSWSS) is characterized by various seizure types, a characteristic EEG pattern and neuropsychological disorders. The main purpose of this study was to evaluate the long-term outcome of CSWSS occurred in childhood and to evaluate the variables that could influence the quality of social adaptation and the personality profile. MATERIAL AND METHODS: This is a prospective study on 24 young adults with previous CSWSS (median age 24.5 yrs) who were enrolled between January and July 2011 at the G. Gaslini Children's Hospital, Genoa, Italy. Patients were divided into two groups: twelve with previous spike-wave index (SWI > 85%) defined as typical CSWSS (T-CSWSS) and twelve with previous SWI = 50-85% defined as atypical CSWSS (A-CSWSS). All the subjects were submitted to Minnesota Multiphasic Personality Inventory-2 (MMPI-2), Psychological General Well-Being Index (PGWBI), and to a structured interview. RESULTS: A correlation was observed with the severity of EEG abnormalities expressed by the SWI and outcome. The T-CSWSS group showed a significantly lower perceived well-being. Similarly in the T-CSWSS group the percentage of MMPI-2 clinical scales with T-scores ≥65 was higher than in the A-CSWSS group. Finally, a significant lower schooling in the T-CSWSS group was observed. CONCLUSION: There seem to be two forms of the same disease, with similar onset and clinical evolution but a different outcome regarding the social and psychological conditions. The outcome of the social adaptation and of the personality consciousness was related with the severity of the EEG abnormalities: more favorable in patients with less intense SWI activity (A-CSWSS) compared those with a more severe EEG impairment (T-CSWSS).

Clinical and electrophysiological features of epilepsy in Italian patients with CLN8 mutations.

Neuronal ceroid lipofuscinoses (NCLs) are characterized by epilepsy, visual failure, psychomotor deterioration, and accumulation of autofluorescent lipopigment. CLN8 mutations result in Northern epilepsy and Turkish variant late infantile NCL. We describe the clinical and neurophysiological findings of three patients with CLN8 mutations from Italy. In these patients, the onset of epilepsy occurred between 3 and 6 years of age, with myoclonic, tonic-clonic, and atypical absence seizures. Electroencephalograms revealed focal and/or generalized abnormalities. In all cases, blindness and progressive attenuation of the electroretinogram were observed. Magnetic resonance imaging revealed cerebral and cerebellar atrophy, thinning of the corpus callosum, deep white matter hyperintensity, and hyperintensity of the posterior limb of internal capsules. Skin biopsy revealed lysosomal storage in the cytoplasm of fibroblasts. The clinical picture of our cases resembles that of the Turkish patients and clearly differs from that of Northern epilepsy, which is marked by a prolonged course without myoclonus and visual loss. Definition of the clinical spectrum of this condition will aid in its recognition and have implications for diagnosis and genetic counseling.

Intractable epilepsy secondary to cyclosporine toxicity in children undergoing allogeneic hematopoietic bone marrow transplantation.

The long-term evolution to intractable epilepsy in children treated with cyclosporine administered for graft-versus-host-disease after hematopoietic stem cell transplantation was evaluated. In a group of 185 children treated with cyclosporine after bone marrow transplantation, 15 (8%) presented with acute seizures that were generalized in 7 and focal in 7 and had absence status in 1. Electroencephalography (EEG) and neuroimaging showed predominant abnormalities in the occipital regions. One patient died shortly after the seizure; in seven cases, seizures remitted, whereas relapses were observed in seven others. After the first year, seizures persisted chronically in four cases and evolved to intractable epilepsy. Focal temporal epilepsy was diagnosed in three cases, whereas in the fourth case, a multifocal epilepsy was observed. Magnetic resonance imaging (MRI) detected mesial temporal sclerosis in all of these cases. The risk factors associated with evolution to epilepsy included lower age at transplantation (3-5 years), more than one relapsing seizure in the first year after transplantation, and longer treatment with cyclosporine. Not only can cyclosporine cause acute central nervous system toxicity, it can also determine intractable epilepsy associated with mesial temporal sclerosis.

No evidence of GABRG2 mutations in severe myoclonic epilepsy of infancy.

Severe myoclonic epilepsy of infancy (SMEI) has been long suspected to have a genetic origin. Recently mutations in the gene encoding a voltage-gated alpha-1 sodium channel subunit-SCN1A-have been identified as a common cause of SMEI. Moreover, a mutation in the gene encoding the gamma2 subunit of the GABA(A) receptor-GABRG2-has been described in a GEFS+ family with a member affected by SMEI. In order to further investigate the role of GABRG2 in the pathogenesis of SMEI, we have screened for mutations 53 SMEI patients who resulted negative for SCN1A mutations. Mutational screening of GABRG2 genes was performed by denaturing high performance liquid chromatography (DHPLC) and direct sequencing of DNA fragments showing a variant chromatogram. Twenty-nine variant chromatograms were identified corresponding to seven different nucleotide variants. None of them leads to an amino acid change or obvious protein dysfunction. No difference in allele frequency was observed for the SMEI patients compared to a control population indicating that these variants are not involved in SMEI. Our study demonstrates that GABRG2 is not a commonly involved in the etiology of SMEI and suggests that other and yet unidentified genes are involved in the syndrome

Early classification of childhood focal idiopathic epilepsies: is it possible at the first seizure?

PURPOSES: To evaluate the possibility of early syndrome classification of idiopathic partial epilepsies in children at the first seizure. PATIENTS AND METHODS: In this observational study we prospectively evaluated 298 patients, aged between 1 month and 17 years and consecutively referred for the first unprovoked focal seizure. The whole cohort included 133 patients; the final analysis was carried out on 107 (59 males) individuals. Age at the first seizure ranged between 2.3 and 13.0 years. Clinical and EEG data of all patients were independently reviewed by two medical doctors. Patients were followed-up for at least 5 years, with a mean period of follow-up of 6.9 years. RESULTS: After the first seizure, a specific syndrome could be diagnosed in eighty (74.7%) children. In particular, Childhood Epilepsy with Centro-Temporal Spikes (CECTS) 42.9% of cases, Panayiotopoulos Syndrome (PS) 28.9%, idiopathic childhood occipital epilepsy of Gastaut (ICOE-G) 2.8%. Unclassified cases were 25.4%. At the end of the follow-up, the diagnosis was confirmed in 72 of 80 children (90%): BCECTS 89% of patients, PS 90% and ICOE-G 100%: among the unclassified cases, in 11 patients (40.7%) the diagnosis did not change, whereas 16 patients (59.3%) evolved into other syndromes or into atypical forms. CONCLUSIONS: At the onset an initial diagnosis is possible in the majority of cases; epilepsy syndromes can be identified at the time of the initial diagnosis and at follow up this diagnosis has not to be revised in 90% of the cases.

Epilepsy associated with supratentorial brain tumors under 3 years of life.

OBJECTIVE: To investigate the clinical features and outcome of epilepsy in children under 3 years of age with supratentorial brain tumors. METHODS: Patients under 3 years with primary supratentorial hemispheric brain tumors were collected during a 10-year period through a database including demographic and clinical features, neuroimaging, tumor location, developmental outcome, pharmacological and surgical treatment, and tumor histology. Postoperative outcome was assessed according to Engel classification. RESULTS: Among 28 children evaluated, twenty (71.4%) suffered from epilepsy. Mean age at seizure onset was 18.7 months (range: 1-60). In fifteen (75%) children, epilepsy was an early manifestation or the presenting symptom of the tumor; seizures were focal in 8 (53.3%) and generalized in 7 (46.7%) individuals. Three (15%) children presented with an epileptic encephalopathy and continuous spike-waves during sleep. Of the five children with epilepsy onset after surgery, four had focal seizures. Post-surgical follow-up ranged from 4 to 10 years (mean: 7.6+/-3.74). The outcome of epilepsy was generally good, with most children (76.4%) being seizure free (Engel I) or showing >90% improvement in seizure frequency (Engel II) after surgery. However, in about 20% of the cases, epilepsy persisted despite surgery and different AEDs regimen. Best epilepsy outcome was observed in patients with low-grade tumors (p<0.01) and without neurological deficits after surgery (p<0.001). CONCLUSIONS: Epilepsy is a common and early symptom in infants with brain tumors. Its outcome is negatively influenced by high tumor malignancy and by the persistence of neurological deficits after surgery. Treatment of these patients needs a multidisciplinary approach.

Clinical and electroencephalographic features in patients with CDKL5 mutations: two new Italian cases and review of the literature.

Clinical features and electroencephalographic findings of two patients affected by a previously unreported cyclin-dependent kinase-like 5 (CDKL5) gene mutation are described. Both patients had the Hanefeld variant phenotype with early-onset seizures, but different degrees of clinical severity. In fact, patient 1 was not drug-resistant and is responding to a single drug. On the contrary, patient 2, like most reported cases, has severe epilepsy, exhibits electroencephalographic changes, and is drug resistant. We suggest that the pseudoperiodic patterns observed on the EEGs for these cases represent this genetic form of epilepsy, though differing in frequency, voltage, and associated patterns. This is in agreement with data reported by other authors indicating that no unique pattern can be identified in subjects with CDKL5 mutations. Thus, a CDKL5 investigation should be performed in developmentally delayed patients with early-onset seizures, including drug-resistant subjects with severe EEG changes, as well as in patients with milder, drug-responsive forms of epilepsy.

Severe epilepsy in X-linked creatine transporter defect (CRTR-D).

Disorders of creatine synthesis or its transporter resulting in neurological impairment with mental retardation and epilepsy have only been recognized in recent years. To date, the epileptic disorder observed in creatine transporter deficiency (CRTR-D) has been described as a mild phenotype with infrequent seizures and favorable response to common antiepileptic drugs. We report on a 5 year-old boy with known speech delay who presented with severe and refractory epilepsy. After extensive investigations, metabolite analysis and brain 1H-MRS suggested CRTR-D, which was confirmed by the detection of a known pathogenic mutation in the SLC6A8 gene (c.1631C>T; p.Pro544Leu).

Brain MRI findings in severe myoclonic epilepsy in infancy and genotype-phenotype correlations.

INTRODUCTION: To determine the occurrence of neuroradiological abnormalities and to perform genotype-phenotype correlations in severe myoclonic epilepsy of infancy (SMEI, Dravet syndrome). PATIENTS AND METHODS: Alpha-subunit type A of voltage-gated sodium channel (SCN1A) mutational screening was performed by denaturing high-performance liquid chromatography (DHPLC) and multiplex ligation probe amplification (MLPA). MRI inclusion criteria were: last examination obtained after the age of 4 years on 1.5-T systems; hippocampal cuts acquired perpendicular to the long axis of the hippocampus; qualitative assessment was performed on T(1)-weighted, T(2)-weighted, proton density, and 1-3 mm thick coronal FLAIR images. RESULTS: We collected 58 SMEI patients in whom last MRI was performed at or later than 4 years of age. SCN1A mutations occurred in 35 (60%) cases. Thirteen (22.4%) out of 58 patients showed abnormal MRIs. Eight patients showed cortical brain atrophy of which 3 associated to ventricles abnormalities, 1 to cerebellar atrophy, 1 to white matter hyperintensity; 3 patients had ventricles enlargement only; 1 patient showed hippocampal sclerosis (HS); 1 had focal cortical dysplasia. Genotype-phenotype analysis indicated that abnormal MRIs occurred more frequently in patients without SCN1A mutations (9/23; 39.1%) compared to those carrying SCN1A mutations (4/35; 11.4%) (p=0.02). CONCLUSION: Different brain abnormalities may occur in SMEI. Only one case with HS was observed; thus, our study does not support the association between prolonged febrile seizures and HS in SMEI. Abnormal MRIs were significantly more frequent in patients without SCN1A mutations. Prospective MRI studies will assess the etiological role of the changes observed in these patients.

Novel mutations in CLN8 in Italian variant late infantile neuronal ceroid lipofuscinosis: Another genetic hit in the Mediterranean.

Neuronal ceroid lipofuscinoses (NCLs) are autosomal recessive neurodegenerative disorders typically characterized by the accumulation of autofluorescent material in tissues. On the basis of clinical features, age at onset, and molecular genetic defects, it is possible to distinguish at least nine forms. The CLN8 form was first described in Finland, where all the patients are homozygous for a p.Arg24Gly mutation in CLN8. More recently, it has been found that a subset of a Turkish variant of late infantile NCL (v-LINCL) is also associated with CLN8 mutations. To identify the molecular defect in Italian patients with v-LINCL, the CLN8 gene was directly sequenced in 10 patients. Controls were screened by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Five fluorescent-labeled microsatellite markers covering 1 cM around the gene were used for haplotype analysis. In three Italian v-LINCL patients, identified in a small area in southern Italy, we detected four new mutations in CLN8: c.66delG (p.Gly22fs), c.88G>C (p.Ala30Pro), c.473A>G (p.Tyr158Cys), and c.581A>G (p.Gln194Arg). The single-base deletion was found in two unrelated patients. The novel missense mutations were not identified in ethnically matched control chromosomes. Our findings expand the number of CLN8 variants and corroborate the notion that CLN8 patients are not confined to the Finnish population.

Somatic and germline mosaicisms in severe myoclonic epilepsy of infancy.

Severe Myoclonic Epilepsy in Infancy (SMEI) is an intractable epileptic syndrome with onset in the first year of life and is commonly caused by de novo mutations in the SCN1A gene, encoding the alpha1-subunit of the neuronal voltage-gated sodium channel. We report two unrelated families in which probands were affected by SMEI and their parents showed a single febrile seizure during early childhood or no neurological symptoms. Semiquantitative analysis of SCN1A mutations allowed the detection of a somatic and germline mosaicism in one of the parents. The study provides the first example of parental mosaicisms in SMEI and opens a new insight into the phenotypic variability and complex inheritance of this condition. The identification of germline mosaicisms has important consequences in genetic counseling of SMEI when SCN1A mutations appear to occur de novo with standard screening methods.

Clinical phenotype and molecular characterization of 6q terminal deletion syndrome: Five new cases.

Mental retardation, facial dysmorphisms, seizures, and brain abnormalities are features of 6q terminal deletions. We have ascertained five patients with 6q subtelomere deletions (four de novo, one as a result of an unbalanced translocation) and determined the size of the deletion ranging from 3 to 13 Mb. Our patients showed a recognizable phenotype including mental retardation, characteristic facial appearance, and a distinctive clinico-neuroradiological picture. Focal epilepsy with consistent electroencephalographic features and with certain brain anomalies on neuroimaging studies should suggest 6q terminal deletion. The awareness of the distinctive clinical picture will help in the diagnosis of this chromosomal abnormality.

6q terminal deletion syndrome associated with a distinctive EEG and clinical pattern: a report of five cases.

PURPOSE: Mental retardation, facial dysmorphisms, and neurologic and brain abnormalities are features of 6q terminal deletions. Epilepsy is frequently associated with this chromosome abnormality, but electroclinical findings are not well delineated. We report five unrelated patients with 6q terminal deletions and a peculiar clinical, EEG, and neuroradiologic picture of epilepsy, mental retardation, and colpocephaly. METHODS: These three male and two female patients underwent general and neurologic examinations, repeated awake and sleep EEGs, and brain magnetic resonance imaging (MRI). A cytogenetic study and fluorescent in situ hybridization (FISH) with chromosome-specific subtelomeric probes were carried out in all cases. RESULTS: All subjects had seizures characterized by vomiting, cyanosis, and head and eye version, with and without loss of consciousness. In four cases, EEGs showed posterior spike-and-wave complexes, which were activated by sleep. No patient had status epilepticus or prolonged seizures. Brain MRI revealed colpocephaly and dysgenesis of the corpus callosum and brainstem in four patients; three of them also had hypertrophic massa intermedia. FISH analysis revealed a 6q terminal deletion in all patients, which ranged between 9 Mb (cases 2 and 3) and 16 Mb (case 4). CONCLUSIONS: We suggest that epilepsy associated with 6q terminal deletions is a new entity. Patients with dysmorphic features associated with focal occipital epilepsy, colpocephaly, and dysgenesis of the corpus callosum, thalami, and brainstem should be considered candidates for testing for 6q subtelomere deletions.

Familial occurrence of febrile seizures and epilepsy in severe myoclonic epilepsy of infancy (SMEI) patients with SCN1A mutations.

PURPOSE: The role of the familial background in severe myoclonic epilepsy of infancy (SMEI) has been traditionally emphasized in literature, with 25-70% of the patients having a family history of febrile seizures (FS) or epilepsy. We explored the genetic background of SMEI patients carrying SCN1A mutations to further shed light on the genetics of this disorder. METHODS: We analyzed the occurrence of FS and epilepsy among first- and second-degree relatives (N = 867) of 74 SMEI probands with SCN1A mutations (70 de novo, four inherited) and compared data with age-matched and ethnically matched control families. Familial clustering and syndromic concordance within the affected relatives in both groups were investigated. RESULTS: The frequency of FS or epilepsy in relatives of SMEI patients did not significantly differ from that in controls (FS: 13 of 867 vs. 12 of 674, p = 0.66; epilepsy: 15 of 867 vs. six of 674, p = 0.16). Different forms of epilepsy were identified in both relatives of SMEI probands and controls. Twenty-eight relatives with FS and epilepsy were distributed in 20 (27%) of 74 SMEI families; among the controls, 18 affected relatives were clustered in 13 (18.5%) of 70 families. No pedigree showed several affected members, including the four with inherited mutations. CONCLUSIONS: A substantial epileptic family background is not present in our SMEI patients with SCN1A mutations. These data do not confirm previous observations and would not support polygenic inheritance in SMEI. The investigation of the family background in additional series of SMEI patients will further shed light on the genetics of this syndrome.

Linkage analysis and disease models in benign familial infantile seizures: a study of 16 families.

PURPOSE: Benign familial infantile seizures (BFIS) is a genetically heterogeneous condition characterized by partial seizures, onset age from 3 to 9 months, and favorable outcome. BFIS loci were identified on chromosomes 19q12-13.1 and 16p12-q12, allelic to infantile convulsions and choreathetosis. The identification of SCN2A mutations in families with only infantile seizures indicated that BFNIS and BFIS may show overlapping clinical features. Infantile seizures also were in a family with familial hemiplegic migraine and mutations in the ATP1A2 gene. We have examined the heterogeneous genetics of BFIS by means of linkage analysis. METHODS: Sixteen families were examined. Probands underwent neurologic examination, at least one EEG recording, and, when possible, brain CT and MRI. Clinical information about relatives was collected. Families with SCN2A or ATP1A2 mutations were excluded from the study. Chromosome 16p and 19q loci were examined by linkage analysis using two models that differed in penetrance rate. Genetic heterogeneity was evaluated with both models. RESULTS: Clinical information was available for 124 members of affected families. BFIS was diagnosed in 69 subjects. One patient without BFIS had a single febrile seizure, and another had rare episodes of paroxysmal dystonia. Evidence of linkage was obtained only for chromosome 16. Moreover, the high penetrance allowed the identification of genetic heterogeneity. CONCLUSIONS: Our data confirm the relevance of the chromosome 16 locus in BFIS and suggest the presence of an additional locus. This study shows that the genetic model used affects the outcome of linkage analysis.

Lack of SCN1A mutations in familial febrile seizures.

PURPOSE: Mutations in the voltage-gated sodium channel subunit gene SCN1A have been associated with febrile seizures (FSs) in autosomal dominant generalized epilepsy with febrile seizures plus (GEFS+) families and severe myoclonic epilepsy of infancy. The present study assessed the role of SCN1A in familial typical FSs. METHODS: FS families were selected throughout a collaborative study of the Italian League Against Epilepsy. For each index case, the entire coding region of SCN1A was screened by denaturant high-performance liquid chromatography. DNA fragments showing variant chromatograms were subsequently sequenced. RESULTS: Thirty-two FS families accounting for 91 affected individuals were ascertained. Mutational analysis detected a single coding variant (A3169G) on exon 16. The extended analysis of all family members and 78 normal controls demonstrated that A3169G did not contribute to the FS phenotype. CONCLUSIONS: Our study demonstrated that SCN1A is not frequently involved in common FSs and suggested the involvement of specific FS genes.