title: Chromosomal microarray testing identifies a 4p terminal region associated with seizures in Wolf-Hirschhorn syndrome.
abstract: BACKGROUND
  Wolf-Hirschhorn syndrome (WHS) is a contiguous gene deletion syndrome involving variable size deletions of the 4p16.3 region. Seizures are frequently, but not always, associated with WHS. We hypothesised that the size and location of the deleted region may correlate with seizure presentation.
  
  
  METHODS
  Using chromosomal microarray analysis, we finely mapped the breakpoints of copy number variants (CNVs) in 48 individuals with WHS. Seizure phenotype data were collected through parent-reported answers to a comprehensive questionnaire and supplemented with available medical records.
  
  
  RESULTS
  We observed a significant correlation between the presence of an interstitial 4p deletion and lack of a seizure phenotype (Fisher's exact test p=3.59e-6). In our cohort, there were five individuals with interstitial deletions with a distal breakpoint at least 751 kbp proximal to the 4p terminus. Four of these individuals have never had an observable seizure, and the fifth individual had a single febrile seizure at the age of 1.5 years. All other individuals in our cohort whose deletions encompass the terminal 751 kbp region report having seizures typical of WHS. Additional examples from the literature corroborate these observations and further refine the candidate seizure susceptibility region to a region 197 kbp in size, starting 368 kbp from the terminus of chromosome 4.
  
  
  CONCLUSIONS
  We identify a small terminal region of chromosome 4p that represents a seizure susceptibility region. Deletion of this region in the context of WHS is sufficient for seizure occurrence.
authors.affiliation: Lineagen, Inc., Salt Lake City, Utah, USA.
authors.forename: Karen S
authors.identifier: http://orcid.org/0000-0003-3217-354X
authors.initials: KS
authors.lastname: Ho
authors.affiliation: ARUP Laboratories, Salt Lake City, Utah, USA Department of Pathology, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Sarah T
authors.initials: ST
authors.lastname: South
authors.affiliation: 4p- Support Group, Sunbury, Ohio, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Lortz
authors.affiliation: Lineagen, Inc., Salt Lake City, Utah, USA.
authors.forename: Charles H
authors.initials: CH
authors.lastname: Hensel
authors.affiliation: Lineagen, Inc., Salt Lake City, Utah, USA.
authors.forename: Mallory R
authors.initials: MR
authors.lastname: Sdano
authors.affiliation: Lineagen, Inc., Salt Lake City, Utah, USA.
authors.forename: Rena J
authors.initials: RJ
authors.lastname: Vanzo
authors.affiliation: Lineagen, Inc., Salt Lake City, Utah, USA.
authors.forename: Megan M
authors.initials: MM
authors.lastname: Martin
authors.affiliation: Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Andreas
authors.initials: A
authors.lastname: Peiffer
authors.affiliation: Department of Internal Medicine, University of New Mexico, Albuquerque, New Mexico, USA.
authors.forename: Christophe G
authors.initials: CG
authors.lastname: Lambert
authors.affiliation: Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Calhoun
authors.affiliation: Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Carey
authors.affiliation: Stella Maris Clinical Research Institute for Child and Adolescent Neuropsychiatry, Pisa, Italy.
authors.forename: Agatino
authors.initials: A
authors.lastname: Battaglia
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002872:Chromosome Deletion; D002894:Chromosomes, Human, Pair 4 / Q000235:genetics*; D056915:DNA Copy Number Variations / Q000235:genetics; D004827:Epilepsy / Q000235:genetics* / Q000473:pathology; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008297:Male; D046228:Microarray Analysis; D012640:Seizures / Q000235:genetics* / Q000473:pathology; D054877:Wolf-Hirschhorn Syndrome / Q000235:genetics* / Q000473:pathology
keywords: Clinical genetics; Epilepsy and seizures; Microarray; Neurology