| Epilepsy Res. 2018 Jan;139:51-53. doi: 10.1016/j.eplepsyres.2017.11.006. Epub 2017 Nov 21.
CNTNAP2 mutations and autosomal dominant epilepsy with auditory features.
Leonardi E1, Dazzo E2, Aspromonte MC1, Tabaro F3, Pascarelli S3, Tosatto SCE3, Michelucci R4, Murgia A1, Nobile C5.
Author information
1Department of Woman and Child's Health, University of Padua, Padova, Italy.2CNR-Neuroscience Institute, Section of Padua, Padova, Italy.3Department of Biomedical Sciences, University of Padua, Padova, Italy.4IRCCS- Institute of Neurological Sciences of Bologna, Unit of Neurology, Bellaria Hospital, Bologna, Italy.5CNR-Neuroscience Institute, Section of Padua, Padova, Italy; Department of Biomedical Sciences, University of Padua, Padova, Italy. Electronic address: [email protected].
Abstract
Autosomal dominant epilepsy with auditory features (ADEAF) is clinically characterized by focal seizures with prominent auditory or aphasic auras and absence of structural brain abnormalities. Mutations in LGI1 and RELN genes account for the disorder in about 50% of ADEAF families. In a recent paper, a heterozygous intragenic deletion in the CNTNAP2 gene has been associated to ADEAF in a single family. We screened 28 ADEAF families for mutations in CNTNAP2 by next generation sequencing and copy number variation analyses and found no likely pathogenic mutations segregating with the disease. CNTNAP2 should be screened in genetically unsolved ADEAF families, but causative mutations are expected to be infrequent in this gene.
https://www.ncbi.nlm.nih.gov/pubmed/?term=...ditory+features
Mutazioni CNTNAP2 e epilessia autosomica dominante con caratteristiche uditive.
Leonardi E1, Dazzo E2, Aspromonte MC1, Tabaro F3, Pascarelli S3, Tosatto SCE3, Michelucci R4, Murgia A1, Nobile C5.
Informazioni sull'autore
1Dipartimento di Donna e Salute del Bambino, Università di Padova, Padova, Italia.2CNR-Istituto di Neuroscienze, Sezione di Padova, Padova, Italia.3 Dipartimento di Scienze Biomediche, Università di Padova, Padova, Italia.4IRCCS- Istituto di Scienze Neurologiche di Bologna, Unità di Neurologia, Ospedale Bellaria, Bologna, Italia.5CNR-Istituto di Neuroscienze, Sezione di Padova, Padova, Italia; Dipartimento di Scienze Biomediche, Università di Padova, Padova, Italia. Indirizzo elettronico: [email protected].
Astratto
Epilessia autosomica dominante con caratteristiche uditive (ADEAF) è clinicamente caratterizzata da crisi focali con aure uditive o afasiche prominenti e assenza di anomalie strutturali del cervello. Le mutazioni nei geni LGI1 e RELN rappresentano il disturbo in circa il 50% delle famiglie ADEAF. In un recente articolo, una delezione eterozigote intratta nel gene CNTNAP2 è stata associata all'ADEAF in una singola famiglia. Abbiamo esaminato 28 famiglie di ADEAF per le mutazioni in CNTNAP2 mediante sequenziamento di prossima generazione e analisi di variazione del numero di copie e non abbiamo trovato mutazioni patogenetiche che segregassero con la malattia. CNTNAP2 deve essere sottoposto a screening in famiglie ADEAF geneticamente non risolte, ma ci si aspetta che le mutazioni causali siano poco frequenti in questo gene.
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CNTNAP2 mutations and autosomal dominant epilepsy with auditory features
Author links open overlay panel Emanuela Leonardi a, Emanuela Dazzo b, Maria Cristina Aspromonte a, Francesco Tabaro c, Stefano Pascarelli c, Silvio C.E. Tosatto c, Roberto Michelucci d, Alessandra Murgia a, Carlo Nobile b, c
Highlights
A CNTNAP2 gene deletion has been reported associated with ADEAF.
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Screening 28 ADEAF families failed to reveal additional CNTNAP2 mutations.
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CNTNAP2 mutations are infrequent in ADEAF.
Abstract
Autosomal dominant epilepsy with auditory features (ADEAF) is clinically characterized by focal seizures with prominent auditory or aphasic auras and absence of structural brain abnormalities. Mutations in LGI1 and RELN genes account for the disorder in about 50% of ADEAF families. In a recent paper, a heterozygous intragenic deletion in the CNTNAP2 gene has been associated to ADEAF in a single family. We screened 28 ADEAF families for mutations in CNTNAP2 by next generation sequencing and copy number variation analyses and found no likely pathogenic mutations segregating with the disease. CNTNAP2 should be screened in genetically unsolved ADEAF families, but causative mutations are expected to be infrequent in this gene.
Introduction
Autosomal dominant epilepsy with auditory features (ADEAF), also named autosomal dominant lateral temporal epilepsy (ADLTE), is clinically characterized by focal seizures with prominent auditory or aphasic auras (Ottman et al., 1995; Michelucci et al., 2003). Mutations in the leucine-rich glioma-inactivated 1 (LGI1) gene are found in about 30% of the ADLTE families (Michelucci et al., 2013), whereas heterozygous mutations in the Reelin (RELN) gene account for about 20% of families (Dazzo et al., 2015). Recently, a heterozygous deletion spanning exons 2–3 of the contactin associated protein-like 2 (CNTNAP2) gene, has been described in a family classifiable as ADEAF (Pippucci et al., 2015), suggesting that CNTNAP2 may be a causal gene for this disorder. We screened CNTNAP2 exons in a series of Italian ADEAF families and failed to identify likely pathogenic variants segregating with the disease.
2. Methods
2.1. Affected families
Affected families were ascertained and DNAs collected by the Genetics Commission Collaborative Group of the Italian League Against Epilepsy. ADEAF families were defined as having two or more affected members with focal seizures characterized by auditory and/or aphasic symptoms, unremarkable magnetic resonance imaging, and relatively benign evolution. Multiplex families in which the proband had typical focal epilepsy with auditory or aphasic features and other members suffered from poorly characterized epilepsy were classified as “possible ADEAF”. Families with LGI1 or RELN mutations were excluded. All participants signed informed consent approved by the Local Ethic Committees.
2.2. High throughput sequencing
CNTNAP2 sequencing was performed by whole exome or massively parallel targeted sequencing. Whole exome sequencing (WES) was performed as described previously (Dazzo et al., 2015). Briefly, high-throughput sequencing of libraries enriched using the SureSelect 50Mb v. 2.0 capture kit (Agilent Technologies) was performed on Illumina HiSeq2000. Reads were aligned on the hg19 reference sequence with BWA (Li and Durbin, 2009). The average coverage of individual CNTNAP2 exons was 52x (range 20–130x). Variant (single nucleotide polymorphism and small insertion-deletion) calling and genotyping was performed with GATK (McKenna et al., 2010). Variants were annotated by ANNOVAR (Wang et al., 2010) and filtered versus 1000 Human Genomes Project (www.1000genomes.org/) and Exome Variant Server (EVS; http://evs.gs.washington.edu/EVS/) catalogs, and AVSIFT (Liu et al., 2011). Allele frequencies of selected variants were also retrieved from Exome Aggregation Consortium (ExAC; http://exac.broadinstoitute.org/) and ExAC V2 plus gnomAD (http://gnomad.broadinstitue.org) databases. The effects of amino acid substitutions on protein function were predicted from PolyPhen-2 (http://genetics.bwh.harvard.edu/pph2/), SIFT (http://sift.jcvi.org/), and Mutation Taster (http://mutationtaster.org/) software tools and Grantham matrix (Grantham, 1974). Massively parallel targeted sequencing (TS) was carried out using Ion PGMTM platform according to the manufacture’s protocols (Life Technologies). A custom Ion Ampliseq panel was used to generate the target amplicon libraries covering the 24 exons and 10 bp of flanking intronic regions of CNTNAP2. Sequence data were processed with the Ion Torrent Suite 5.0. The average coverage of individual CNTNAP2 exons was 377x (range 261–745x). As with WES, variants were annotated with ANNOVAR (Wang et al., 2010) and bioinformatic analysis was carried out as described above.
The CNTNAP2 fibrinogen-like (FBG) domain was built using as template the FBG domain of alpha-Collagen predicted with HHpred and modelled with MODELLER (automatic best template selection), using the integrative platform of MPI bioinformatics toolkit (Alva et al., 2016).
2.3. CNV analysis
For copy number variation (CNV) analysis, affected and nonaffected family members of 16 families were genotyped with the HumanOmni1-Quad v1.0 beadchip (Illumina), which includes 1,140,419 single nucleotide polymorphisms (SNPs), on Illumina Iscan System, as described previously (Fanciulli et al., 2014). The PennCNV algorithm (Wang et al., 2007) was used to infer CNVs from signal intensity data in the CNTNAP2 region. Parameters were set to consider only imbalances >10 kb. In addition, CNV analysis of eight family probands was performed from targeted sequencing data using the CoNVaDING software pipeline (Johansson et al., 2016). The method implements a depth-of-reads approach and features automatic control sample selection. A CNTNAP2 representative set of exons was selected based on reads coverage, exon length and amplification propensity. The CoNVaDING analysis was run using either standard parameters or relaxing the Z-score thresholds to ±2, while not altering score ratios and region threshold values. For each patient, on average, 60 candidate structural alterations were detected but none passed the final quality filter, even with more relaxed thresholds. Moreover, unsupervised clustering and quartile mean based statistics were performed on coverage data (data not shown).
3. Results
CNTNAP2 (NM_014141) exon sequencing was performed in 1–2 affected members of 28 ADEAF families by WES (19 families) or massively parallel targeted sequencing (9 families), and CNV analysis was performed in 24 families (Table 1). Most families have been clinically described previously (Michelucci et al., 2013). Whereas CNV analysis did not reveal any deletion or duplication in CNTNAP2, high throughput sequencing detected a heterozygous nonsynonymous variant, c.2339C > T, (p.Ser780Leu), in family F19, which was validated by Sanger sequencing (Fig. 1A and B). This variant is not present in the EVS and ExAC population databases, and occurs only once (frequency: 0.000004) in the ExAC V2 plus gnomAD database; it is predicted to be protein damaging by several software tools, including PolyPhen2 (score: 0.952) SIFT (score: 0.01), Mutation Taster (probability: 0.999), and Grantham Matrix (score: 145). The Ser780 residue is highly conserved across vertebrate species in the CNTNAP2 protein and other members of the CNTNAP protein family (Fig. 1C), and 3D protein modelling shows that it may be important for interaction of CNTNAP2 with partner proteins, given its position on the surface of the fibrinogen-like (FBG) domain (Fig. 1D). However, the p.Ser780Leu substitution did not segregate with ADEAF in family F19 (Fig. 1A), which does not support a dominant pathogenic role for this variant.
https://www.sciencedirect.com/science/arti...4461?via%3Dihub
CNTNAP2 mutations and autosomal dominant epilepsy with auditory features
Emanuela Leonardi, Emanuela Dazzo, Maria Cristina Aspromonte, Francesco Tabaro, Stefano Pascarelli, Silvio C.E. Tosatto, Roberto Michelucci, Alessandra Murgia, Carlo Nobile
Istituto Scienze Neurologiche
https://moh-it.pure.elsevier.com/en/public...with-auditory-fEpilessia autosomica dominante notturna del lobo frontale
L'epilessia notturna autosomica dominante del lobo frontale (ADNFLE dall'inglese ovvero Autosomal Dominant Nocturnal Frontal Lobe Epilepsy) è una rara forma epilessia parziale di recente inquadramento nosografico che causa frequenti crisi epilettiche violente durante il sonno. Durante dette crisi si compiono spesso complessi movimenti notturni quali pugni serrati, innalzamento o abbassamento delle braccia e piegamento delle ginocchia. Molto comuni risultano essere anche vocalizzazioni come grida, gemiti o pianto.
L'epilessia notturna autosomica dominante del lobo frontale è spesso erroneamente diagnosticata come incubi notturni in quanto presenta sintomi afferenti alle parasonnie. Si contano quattro loci conosciuti in merito a questa epilessia parziale, tre dei quali comprendenti gene causativi che codificano differenti subunità del recettore nicotinico.
L'epilessia notturna autosomica dominante del lobo frontale è un'epilessia parziale caratterizzata da brevi crisi epilettiche violente durante il sonno. Queste crisi complesse consistono nel movimento degli arti, la chiusura serrata dei pugni e vocalizzazioni come grida e gemiti. Dette crisi epilettiche avvengono in serie ravvicinata e si possono manifestare sin dall'infanzia. A questo proposito, occorre segnalare che quest'epilessia spesso è mal diagnosticata come incubi, incubi notturni, parasonnie e vari ed eventuali disturbi psichiatrici che presentano sintomi simili.
Sebbene non ancora del tutto intesa, si ritiene che la causa di questa epilessia parziale sia un malfunzionamento delle formazioni reticolari del nucleo talamico il cui ruolo è centrale nella malattia. I motivi per cui si è giunti a tale conclusione sono essenzialmente tre: in primo luogo, la funzione delle formazioni reticolari è importante nel sonno e le crisi epilettiche tipiche dell'epilessia notturna autosomica dominante del lobo frontale hanno origine nella corteccia frontale; in secondo luogo, sia il talamo, sia la corteccia ricevono impulsi colinergici e le subunità del recettore dell'acetilcolina comprendono i tre geni noti causanti detta epilessia. In ultimo, i complessi K rimangono alquanto invariati sin dall'inizio delle crisi epilettiche.[1]
La diagnosi si formula in base alla storia clinica del paziente sebbene un riscontro tramite elettroencefalografia può avere carattere probatorio, se avvengono delle crisi durante l'esame.
https://it.wikipedia.org/wiki/Epilessia_au...l_lobo_frontale
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