title: Parental mosaicism in another case of Dravet syndrome caused by a novel SCN1A deletion: a case report.
abstract: BACKGROUND
  Dravet syndrome, a rare genetic disorder with early-onset epileptic encephalopathy, was first described by Dravet in 1978. Dravet syndrome is most frequently caused by various mutations of the SCN1A gene encoding the type 1 subunit of the neuronal voltage-gated sodium channel.
  
  
  METHODS
  Two sisters of a non-consanguineous Palestinian family from the Arab community in Israel attended our child development and pediatric neurology clinic due to recurrent seizures and developmental delay. Genomic DNA was extracted from peripheral blood lymphocytes of all family members and a SCN1A mutation in exon 10 was revealed by Sanger sequencing in both affected siblings but not in the parents. Our data present a case of Dravet syndrome caused by a novel heterozygous SCN1A deletion (c.1458_1465delCTCTAAGT) in two affected siblings. Our findings add to the spectrum of mutations known in the SCN1A gene and confirm parental mosaicism as a mechanism relevant for transmission of this disease.
  
  
  CONCLUSIONS
  These cases confirm parental mosaicism in the transmission of Dravet syndrome and add to the spectrum of known mutations of the SCN1A gene. Repeated reports on parental mosaicism should remind us that there is a risk of recurrence even if the mutation is apparently de novo.
authors.affiliation: The Triangle Regional Research and Development Center, P. O. Box-2167, Kfar Qari', 30075, Israel. rajachsharkia@hotmail.com.|Beit-Berl Academic College, Beit-Berl, 44905, Israel. rajachsharkia@hotmail.com.
authors.forename: Rajech
authors.initials: R
authors.lastname: Sharkia
authors.affiliation: German Research Center for Neurodegenerative Diseases (DZNE), 72076, Tübingen, Germany.|Department of Neurodegenerative Diseases and Hertie-Institute for Clinical Brain Research, University of Tübingen, Hoppe-Seyler Str. 3, 72076, Tübingen, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Hengel
authors.affiliation: German Research Center for Neurodegenerative Diseases (DZNE), 72076, Tübingen, Germany.|Department of Neurodegenerative Diseases and Hertie-Institute for Clinical Brain Research, University of Tübingen, Hoppe-Seyler Str. 3, 72076, Tübingen, Germany.
authors.forename: Ludger
authors.initials: L
authors.lastname: Schöls
authors.affiliation: The Triangle Regional Research and Development Center, P. O. Box-2167, Kfar Qari', 30075, Israel.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Athamna
authors.affiliation: Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Bauer
authors.affiliation: Child Neurology and Development Center, Hillel-Yaffe Medical Center, 38100, Hadera, Israel. mohamedm@hy.health.gov.il.|Bruce and Ruth Rappaprt Faculty of Medicine, Technion, 31096, Haifa, Israel. mohamedm@hy.health.gov.il.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Mahajnah
mesh_terms: D044466:Asian People; D002648:Child; D002675:Child, Preschool; D004831:Epilepsies, Myoclonic / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D006801:Humans; D040582:Inheritance Patterns; D008969:Molecular Sequence Data; D009030:Mosaicism; D062550:NAV1.1 Voltage-Gated Sodium Channel / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010375:Pedigree; D017422:Sequence Analysis, DNA; D035781:Siblings; D015222:Sodium Channels / Q000235:genetics
chemical_list: D062550:NAV1.1 Voltage-Gated Sodium Channel; D009419:Nerve Tissue Proteins; C568242:SCN1A protein, human; D015222:Sodium Channels
keywords: Dravet syndrome; Genetic counseling; Paternal mosaicism; SCN1A gene