No abstract available.
Epilepsy, Benign Neonatal*

Epilepsy, Benign Neonatal ; genetics ; Humans

OBJECTIVEThe present study performed linkage analysis and gene mapping to find the possible chromosome locus harboring in one family with benign familial infantile convulsions (BFIC) and investigate the possible molecular pathogenesis of BFIC.

METHODSA four-generation family with BFIC was investigated. The family was genotyped using eight hypervariable microsatellite markers covering four loci: D19S245 and D19S250 for the 19q12-13.1 region, D16S3131 and D16S3133 for the 16p12-q12 region, D2S156 and D2S286 for the 2q24 region, and D20S480 and D20S481 for the 20q13.3 region. Polymorphism fragments were amplified using polymerase chain reaction (PCR) method. PCR products for the markers were subjected to electrophoresis on 8% denatured polyacrylamide gel and silver staining for length judgment of amplification fragment. Linkage analysis was performed by use of MLINK in the LINKAGE computer package. Two-point LOD scores were calculated to estimate the linkage relationship.

RESULTSThe two-point LOD scores were less than -2.0 for the genetic markers at chromosomes 19q12-13.1, 16p12-q12 and 2q24 at the recombination rate between 0.000 and 0.01. The two-point LOD scores for D20S481 at the 20q13.3 region were 0.3 and 0.25 at the recombination rate of 0.000 and 0.01, respectively.

CONCLUSIONSThere is no evidence that this family with BFIC is linked to one of the following loci: 19q12-13.1, 16p12-q12 and 2q24, but a possible linkage with 20q13.3 region cannot be excluded.

Chromosome Mapping ; Epilepsy, Benign Neonatal ; genetics ; Female ; Genetic Linkage ; Humans ; Lod Score ; Male ; Microsatellite Repeats

Benign idiopathic neonatal convulsion is a rare disorder which has no family history of convulsion and develops before and after the 5th day in a healthy full-term neonate. Its characteristics appear focal, or multifocal clonic seizures but rare tonic seizures lasting about several minutes. It reveals non-specific findings in neurologic examination, neuroimaging and EEG(electroencephalography) so that it should be differentiated from those diseases such as eletronic imbalance, inborn errors of metabolism, other neonatal epileptic syndromes. We report two healthy full-term female neonates presented with multifocal clonic seizures before and after the 5th day after birth. They had no family history of convulsion, fetal asphyxia, fetal and maternal problems and the neurologic examination and neuroimagings were normal. The convulsions were controlled by intravenous phenobarbital injection. They had no more convulsions ever since and showed normal development at the follow-up performed one year later. We experienced a rare disorder, benign neonatal convulsion in healthy full-term neonates. We hope this report will help its diagnosis and treatment and prevent unnecessary long- term anticonvulsant medication.
Asphyxia ; Epilepsy, Benign Neonatal ; Female ; Follow-Up Studies ; Humans ; Infant, Newborn ; Metabolism, Inborn Errors ; Neuroimaging ; Neurologic Examination ; Parturition ; Phenobarbital ; Seizures

Proline-rich transmembrane protein 2 (PRRT2) is the leading cause of paroxysmal kinesigenic dyskinesia (PKD), benign familial infantile epilepsy (BFIE), and infantile convulsions with choreoathetosis (ICCA). Reduced penetrance of PRRT2 has been observed in previous studies, whereas the exact penetrance has not been evaluated well. The objective of this study was to estimate the penetrance of PRRT2 and determine its influencing factors. We screened 222 PKD index patients and their available relatives, identified 39 families with pathogenic or likely pathogenic (P/LP) PRRT2 variants via Sanger sequencing, and obtained 184 PKD/BFIE/ICCA families with P/LP PRRT2 variants from the literature. Penetrance was estimated as the proportion of affected variant carriers. PRRT2 penetrance estimate was 77.6% (95% confidence interval (CI) 74.5%-80.7%) in relatives and 74.5% (95% CI 70.2%-78.8%) in obligate carriers. In addition, we first observed that penetrance was higher in truncated than in non-truncated variants (75.8% versus 50.0%, P = 0.01), higher in Asian than in Caucasian carriers (81.5% versus 68.5%, P = 0.004), and exhibited no difference in gender or parental transmission. Our results are meaningful for genetic counseling, implying that approximately three-quarters of PRRT2 variant carriers will develop PRRT2-related disorders, with patients from Asia or carrying truncated variants at a higher risk.
Dystonia ; Epilepsy, Benign Neonatal/genetics* ; Humans ; Membrane Proteins/genetics* ; Mutation ; Nerve Tissue Proteins/genetics* ; Pedigree ; Penetrance ; Seizures/genetics*

OBJECTIVE: To analyze the clinical phenotype and genetic variant in a Chinese pedigree affected with benign familial neonatal convulsion (BFNC). METHODS: Clinical data and peripheral blood samples of the pedigree were obtained with informed consent. Whole exome sequencing (WES) was carried out for the proband. Candidate variants were verified by Sanger sequencing. RESULTS: The pedigree comprised 9 individuals, among whom 4 were affected, including 3 males and 1 female. All patients had developed seizures during the neonatal period, which had ceased in 4 to 6 months. One patient had recurrence in between 1 and 2 years old. Genetic testing has identified a novel nonsense c.810G>A (p.W270X) variant in exon 5 of the KCNQ2 gene, which has co-separated with the BFNC phenotype in the pedigree. CONCLUSION The patients from this pedigree have conformed to the diagnosis of BFNC with good prognosis, which was in keeping with previously reported cases. The heterozygous c.810G>A (p.W270X) nonsense variant of the KCNQ2 gene probably underlay the pathogenesis of BFNC in this pedigree, which has expanded the mutational spectrum of the disease.
Asians/genetics* ; Child, Preschool ; China ; Epilepsy, Benign Neonatal/genetics* ; Female ; Genetic Testing ; Humans ; Infant ; Male ; Mutation ; Pedigree

OBJECTIVETo diagnose a Chinese benign familial neonatal convulsions (BFNC) family at the level of gene and investigate its molecular pathogenesis.

METHODSAll family members were studied by clinical examinations and linkage analysis. Mutation analysis of KCNQ2 gene was made by means of polymerase chain reaction (PCR)-direct sequencing and PCR-single strand conformation polymorphism (SSCP) in the proband, 16 family members and 72 unrelated normal individuals.

RESULTSLinkage analysis hinted the linkage of BFNC to KCNQ2, while the linkage to KCNQ3 was excluded. Mutation 1931delG of KCNQ2 gene was found in the proband by DNA-direct sequencing. The same SSCP variant as the proband's was showed in the rest affected members of this family but not in the unaffected members of this family and all of the 72 unrelated normal individuals.

CONCLUSION1931delG of KCNQ2 gene can cause BFNC in China and is novel mutation. The combination of linkage analysis and gene analysis is useful for gene diagnosis.

Epilepsy, Benign Neonatal ; genetics ; Female ; Genetic Linkage ; Humans ; Infant, Newborn ; KCNQ2 Potassium Channel ; KCNQ3 Potassium Channel ; Mutation ; Potassium Channels ; chemistry ; genetics ; Potassium Channels, Voltage-Gated

OBJECTIVETo study the protocol of construction of a KCNQ2-c.812G>T mutant and it's eukaryotic expression vector, the c.812G>T (p.G271V) mutation which was detected in a Chinese pedigree of benign familial infantile convulsions, and to examine the expression of mutant protein in human embyonic kidney (HEK) 293 cells.

METHODSA KCNQ2 mutation c.812G>T was engineered on KCNQ2 cDNAs cloned into pcDNA3.0 by sequence overlap extension PCR and restriction enzymes. HEK293 cells were co-transfected with pRK5-GFP and KCNQ2 plasmid (the wild type or mutant) using lipofectamine and then subjected to confocal microscopy. The transfected cells were immunostained to visualize the intracellular expression of the mutant molecules.

RESULTSDirect sequence analysis revealed a G to T transition at position 812. The c.812G>T mutation was correctly combined to eukaryotic expressive vector pcDNA3.0 and expressed in HEK293 cells. Immunostaining of transfected cells showed the expression of both the wild type and mutant molecules on the plasma membrane, which suggested that the c.812G>T mutation at the pore forming region of KCNQ2 channel did not impair normal protein expression in HEK293 cells.

CONCLUSIONSSuccessful construction of mutant KCNQ2 eukaryotic expression vector and expression of KCNQ2 protein in HEK293 cells provide a basis for further study on the functional effects of convulsion-causing KCNQ2 mutations and for understanding the molecular pathogenesis of epilepsy.

Epilepsy, Benign Neonatal ; genetics ; Fluorescent Antibody Technique ; Genetic Vectors ; HEK293 Cells ; Humans ; Infant, Newborn ; KCNQ2 Potassium Channel ; analysis ; genetics ; physiology ; Mutagenesis, Site-Directed ; Polymerase Chain Reaction

OBJECTIVEBenign familial infantile convulsions (BFIC) is a recently recognized autosomal dominant inherited disorder. This epileptic syndrome typically begins between 3 and 12 months of age with clusters of partial seizures in most cases and carries a good prognosis. So far, three loci have been linked to chromosome 19q12.1-13.1, chromosome 2q24 and chromosome 16p12-q12. The authors performed linkage analysis on this pedigree.

METHODSA four-generation Chinese family was investigated. The total number of members was 32 in this family and two neurologists in Xiangya Hospital gave systemic physical examinations and interictal neurological examinations to nineteen members of this family. Venous blood samples were taken for genetic analysis. DNA was extracted from peripheral blood leukocytes using phenol-chloroform method. Seventeen microsatellite markers spanning the critical regions on chromosomes 19q12-13.1, 2q24, and 16p12-q12 were genotyped. These markers included D19S49, D19S250, D19S414, D19S416 and D19S245 for the 19q region, D2S2380, D2S399, D2S111, D2S2195, D2S2330 and D2S2345 for the 2q region, D16S401, D16S3131, D16S3093, D16S517, D16S3120 and D16S415 for the 16p-q region. The DNA from each sample was amplified for the 17 markers. After polymerase chain reactions (PCR), PCR products of chromosome 19 with markers D19S49, D19S250, D19S414, D19S416 and D19S245 were subjected to electrophoresis on 8% denatured polyacrylamide gel for at least 2 hours and 20 minutes. Then the length of the PCR products was judged in the Strategene Eagle Eye II automated gel image analyzer. For the markers from chromosome 2 and 16, PCR products were scanned at ABI 377 autosequencer. The data of PCR products were analyzed using the software Genescan v3.1, Genetyper v2.1 (Applied Biosystem, CA. USA) and GenoDB v1.0. After Mendelian checking, the eligible genotyping data were used for linkage analysis. LOD scores were calculated by using MLINK program of LINKAGE v5.1, under an assumption of autosomal dominant inheritance and the estimated penetrance was 0.9. The allele frequencies of each marker were assumed to be equal and the disease-allele frequencies were designated to be 1/10,000. The LOD scores were calculated at combination rate (theta) 0.0, 0.1, 0.2, 0.3, and 0.4.

RESULTSAmong the 17 selected microsatellite markers, which cover the previously reported regions, seven markers' data (D16S3131, D16S517, D16S3120, D16S3093, D2S2380, D19S250 and D19S414) were omitted due to failed genotyping, low genetic heterogeneity, or failure to pass Mendelian checking. Omission of these markers was to ensure the reliability of our raw data. The two-point LOD scores were below zero for all the markers and the maximum LOD scores at theta = 0.0 were less than -2 for markers D19S49, D19S416, D19S245, D16S401, D16S415, D2S399, D2S111, D2S2195, D2S2330 and D2S2345. Thus, the linkage result showed no evidence that the disease locus is linked to any of these selected markers, which excludes the previously reported candidate regions found in other ethnic families.

CONCLUSIONThere is no evidence that this Chinese family was linked to one of the following loci: 19q12.1-13.1, 16p12-q12 and 2q24. The results indicated that BFIC showed genetic heterogeneity and the Chinese BFIC families might be mapped on another new locus.

China ; Epilepsy, Benign Neonatal ; genetics ; Family Health ; Female ; Gene Frequency ; Genetic Heterogeneity ; Genetic Linkage ; Genetic Markers ; Humans ; Infant ; Lod Score ; Male ; Microsatellite Repeats ; Pedigree ; Polymerase Chain Reaction

Neonatal seizures represent a heterogeneous group of disorders with vastly different etiologies and outcomes. Benign familial neonatal convulsions (BFNC) are a distinctive epileptic syndrome of autosomal dominant inheritance with a favorable prognosis, characterized by the occurrence of unprovoked partial or generalized clonic seizures in the neonatal period or early infancy. Recently, mutations in two potassium channel genes, KCNQ2 and KCNQ3, have been described in this disorder. In this report, we describe a family with BFNC due to a KCNQ2 mutation, the first such family to be described in the Korean population. The diagnosis of BFNC can be made based on clinical suspicion and careful history taking with special emphasis on the familial nature of the disorder. KCNQ2 mutations may be associated with BFNC in a number of different races, as has been reported in other ethnic groups.
Electroencephalography ; Epilepsy, Benign Neonatal/*diagnosis/genetics ; Female ; Humans ; Infant, Newborn ; KCNQ2 Potassium Channel/*genetics ; Magnetic Resonance Imaging ; Mutation ; Pedigree ; Republic of Korea ; Sequence Analysis, DNA