Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0009952 (febrile convulsions)
 1,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently described mutations of the neuronal sodium-channel alpha-subunit gene, SCN1A, on chromosome 2q24 in two families with generalized epilepsy with febrile seizures plus (GEFS+) type 2. To assess the contribution that SCN1A makes to other types of epilepsy, 226 patients with either juvenile myoclonic epilepsy, absence epilepsy, or febrile convulsions were screened by conformation-sensitive gel electrophoresis and manual sequencing of variants; the sample included 165 probands from multiplex families and 61 sporadic cases. The novel mutation W1204R was identified in a family with GEFS+. Seven other coding changes were observed; three of these are potential disease-causing mutations. Two common haplotypes, with frequencies of .67 and .33, were defined by five single-nucleotide polymorphisms (SNPs) spanning a 14-kb region of linkage disequilibrium. An SNP located 18 bp upstream of the splice-acceptor site for exon 3 was observed in 7 of the 226 patients but was not present in 185 controls, suggesting possible association with a disease mutation. This work has confirmed the role of SCN1A in GEFS+, by identification of a novel mutation in a previously undescribed family. Although a few candidate disease alleles were identified, the patient survey suggests that SCN1A is not a major contributor to idiopathic generalized epilepsy. The SCN1A haplotypes and SNPs identified here will be useful in future association and linkage studies.
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PMID:A novel SCN1A mutation associated with generalized epilepsy with febrile seizures plus--and prevalence of variants in patients with epilepsy. 1125 45

Evidence that febrile seizures have a strong genetic predisposition has been well documented. In families of probands with multiple febrile convulsions, an autosomal dominant inheritance with reduced penetrance is suspected. Four candidate loci for febrile seizures have been suggested to date; FEB1 on 8q13-q21, FEB2 on 19p, FEB3 on 2q23-q24, and FEB4 on 5q14-15. A missense mutation was identified in the voltage-gated sodium (Na(+))-channel beta 1 subunit gene, SCN1B at chromosome 19p13.1 in generalized epilepsy with the febrile seizures plus type 1 (GEFS+1) family. Several missense mutations of the (Na(+))-channel alpha 1 subunit (Nav1.1) gene, SCN1A were also identified in GEFS+2 families at chromosome 2q23-q24.3. The aim of this report is precisely to describe the phenotypes of Japanese patients with novel SCN1A mutations and to reevaluate the entity of GEFS+. Four family members over three generations and one isolated (phenotypically sporadic) case with SCN1A mutations were clinically investigated. The common seizure type in these patients was febrile and afebrile generalized tonic-clonic seizures (FS+). In addition to FS+, partial epilepsy phenotypes were suspected in all affected family members and electroencephalographically confirmed in three patients of two families. GEFS+ is genetically and clinically heterogeneous, and associated with generalized epilepsy and partial epilepsy as well. The spectrum of GEFS+ should be expanded to include partial epilepsies and better to be termed autosomal dominant epilepsy with febrile seizures plus (ADEFS+).
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PMID:Autosomal dominant epilepsy with febrile seizures plus with missense mutations of the (Na+)-channel alpha 1 subunit gene, SCN1A. 1182 6

Febrile seizures affect 2-5% of all children younger than 6 years. A small proportion of children with febrile seizures later develop epilepsy. The syndrome of generalized epilepsy with febrile seizures plus (GEFS+) is a heterogeneous disorder characterized by febrile seizures that may persist beyond age 6 years and nonfebrile seizures. Several genes have been localized for FS by linkage analysis, and three GEFS+ genes (SCN1A, SCN1B, GABRG2) have been identified. We identified a large multigenerational family with GEFS+ in France. All affected members had FSs. Among them, seven had other types of epileptic seizures including FSs after age 6 years, nonfebrile generalized seizures, or partial seizures later in life. Genetic linkage study excluded the candidate genes and loci for FS and GEFS+, thus proving the existence of a new GEFS+ genetic locus underlying the phenotype observed in this family.
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PMID:Clinical and genetic analysis of a new multigenerational pedigree with GEFS+ (Generalized Epilepsy with Febrile Seizures Plus). 1206 16

Febrile seizures are the most common form of convulsion, occurring in 2-5% of infants in Europe and North America and in 6-9% in Japan. In large families, the febrile seizure (FS) susceptibility trait is inherited by the autosomal dominant pattern with reduced penetrance. Two putative FS loci, FEB1 (chromosome 8q13-q21) and FEB2 (chromosome 19p13.3) have been mapped. A clinical subset of FS, termed generalized epilepsy with febrile seizures plus (GEFS+), was reported. In GEFS+ families, a mutation in the voltage-gated sodium channel beta1 subunit gene (SCN1B) at chromosome 19q13.1 and two mutations of the same alpha1 subunit gene (SCN1A) at chromosome 2q24 were identified. These loci are linked to febrile convulsions in large families. We conducted a genome-wide linkage search for FS in one large family with subsequent linkage confirmation in 39 nuclear families using nonparametric allele-sharing methods, and found a new FS susceptibility locus, FEB4 (chromosome 5q14-q15). In contrast to the FEB1, FEB2, and GEFS+ genetic loci, linkage to FEB4 was suggested in nuclear FS families, indicating that FEB4 may be the most common linkage locus in FS families.
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PMID:Molecular genetics of febrile seizures. 1238 77

Febrile convulsions (FCs) represent the majority of childhood seizures, and patients have a genetic predisposition to their development. The genetic susceptibility to FCs seems to involve multiple genes in most instances. Recent studies provided evidence that mutations in SCN1A represent the most frequent cause of generalized epilepsy with febrile seizures plus an autosomal-dominant epilepsy syndrome. SCN1A mutations alter channel inactivation, resulting in persistent inward sodium current. It is not known if polymorphisms in those genes involved in familial epilepsies also contribute to the pathogenesis of FCs. By performing an association study, we used single nucleotide polymorphisms to investigate the distribution of genotypes of SCN1A in patients with FCs. A total of 104 Taiwanese children with FCs and 83 normal control subjects were included in the study. Polymerase chain reaction was used to identify the A/G polymorphism of the SCN1A gene. The results showed that genotypes and allelic frequencies for the SCN1A gene polymorphisms in both groups were not significantly different. These data suggest that the SCN1A gene might not be one of the susceptibility factors for FCs. Pure FCs and febrile convulsions associated with idiopathic generalized epilepsy may not share a common genetic etiology.
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PMID:The lack of association between febrile convulsions and polymorphisms in SCN1A. 1274 96

Febrile seizures (FS) represent the most common seizure disorder in childhood and contribution of a genetic predisposition has been clearly proven. In some families FS is associated with a wide variety of afebrile seizures. Generalized epilepsy with febrile seizures plus (GEFS+) is a familial epilepsy syndrome with a spectrum of phenotypes including FS, atypical febrile seizures (FS+) and afebrile generalized and partial seizures. Mutations in the genes SCN1B, SCN1A and GABRG2 were identified in GEFS+ families. GEFS+ is genetically heterogeneous and mutations in these three genes were detected in only a minority of the families. We performed a 10 cM density genome-wide scan in a multigenerational family with febrile seizures and epilepsy and obtained a maximal multipoint LOD score of 3.12 with markers on chromosome 5q14.3-q23.1. Fine mapping and segregation analysis defined a genetic interval of approximately 33 cM between D5S2103 and D5S1975. This candidate region overlapped with a previously reported locus for febrile seizures (FEB4) in the Japanese population, in which MASS1 was proposed as disease gene. Mutation analysis of the exons and exon-intron boundaries of MASS1 in our family did not reveal a disease causing mutation. Our linkage data confirm for the first time that a locus on chromosome 5q14-q23 plays a role in idiopathic epilepsies. However, our mutation data is negative and do not support a role for MASS1 suggesting that another gene within or near the FEB4 locus might exist.
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PMID:Genome-wide linkage of febrile seizures and epilepsy to the FEB4 locus at 5q14.3-q23.1 and no MASS1 mutation. 1627 91

Febrile seizures (FS) affect 5-12% of infants and children up to 6 years of age. There is now epidemiological evidence that FS are associated with subsequent afebrile and unprovoked seizures in approximately 7% of patients, which is 10 times more than in the general population. Extensive genetic studies have demonstrated that various loci are responsible for familial FS, and the FEB3 autosomal-dominant locus has been identified on chromosome 2q23-24, where the SCN1A gene is mapped. However, gene mutations causing simple FS have not been found yet. Here we show that the M145T mutation of a well conserved amino acid in the first transmembrane segment of domain I of the human Na(v)1.1 channel alpha-subunit cosegregates in all 12 individuals of a large Italian family affected by simple FS. Functional studies in mammalian cells demonstrate that the mutation causes a 60% reduction of current density and a 10-mV positive shift of the activation curve. Thus, M145T is a loss-of-function mutant. These results show that monogenic FS should also be considered a channelopathy.
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PMID:Identification of an Nav1.1 sodium channel (SCN1A) loss-of-function mutation associated with familial simple febrile seizures. 1632 7

A 10-year-old boy developed febrile convulsions at age 2 years, and multiple types of nonfebrile generalized seizures over the ensuing months and years. Gestation, birth, and early development were normal, as were initial EEG and brain imaging studies. By age 5 years, he had developed behavioral difficulties, and the EEG demonstrated both interictal and ictal generalized epileptiform patterns, as well as mild background slowing. Seizures were poorly controlled with multiple medication trials. There was a strong family history of clinically benign febrile seizures in the maternal lineage. Genetic analysis revealed a novel mutation in the voltage-gated neuronal sodium channel SCN1A. This patient's relatively malignant clinical course is consistent with "extended spectrum" generalized epilepsy with febrile seizures plus (GEFS+), and along with the family history illustrates the phenotypic variability of this disease.
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PMID:A case of extended spectrum GEFS+. 1635 70

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.
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PMID:Somatic and germline mosaicisms in severe myoclonic epilepsy of infancy. 1643 Aug 63

Febrile seizures (FSs) represent the most common form of childhood seizures, occurring in 2-5% of infants in Europe and North America and in 6-9% in Japan. It has been recognized that there is a significant genetic component for susceptibility to this type of seizure. Six susceptibility FS loci have been identified on chromosomes 8q13-q21 (FEB1), 19p (FEB2), 2q23-q24 (FEB3), 5q14-q15 (FEB4), 6q22-q24 (FEB5), and 18p11 (FEB6). Furthermore, mutations in the voltage-gated sodium channel alpha-1, alpha-2 and beta-1 subunit genes (SCN1A, SCN2A and SCN1B) and the GABA(A) receptor gamma-2 subunit gene (GABRG2) have been identified in families with a clinical subset of seizures termed "generalized epilepsy with febrile seizure plus (GEFS+)". However, the causative genes have not been identified in most patients with FSs or GEFS+. Common forms of FSs are genetically complex disorders believed to be influenced by variations in several susceptibility genes. Recently, several association studies in FSs have been reported, but the results vary among different groups and no consistent or convincing FS susceptibility genes have emerged. To find a true association, larger sample size and newer methodologic refinements are recommended.
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PMID:Molecular genetics of febrile seizures. 1688 33


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