2. Academic Validation
  3. Chromosomal microarray testing identifies a 4p terminal region associated with seizures in Wolf-Hirschhorn syndrome

Chromosomal microarray testing identifies a 4p terminal region associated with seizures in Wolf-Hirschhorn syndrome

  • J Med Genet. 2016 Apr;53(4):256-63. doi: 10.1136/jmedgenet-2015-103626.
Karen S Ho 1,  Sarah T South 2,  Amanda Lortz 3,  Charles H Hensel 1,  Mallory R Sdano 1,  Rena J Vanzo 1,  Megan M Martin 1,  Andreas Peiffer 4,  Christophe G Lambert 5,  Amy Calhoun 6,  John C Carey 4,  Agatino Battaglia 7
Affiliations

Affiliations

  • 1 Lineagen, Inc., Salt Lake City, Utah, USA.
  • 2 ARUP Laboratories, Salt Lake City, Utah, USA Department of Pathology, University of Utah, Salt Lake City, Utah, USA.
  • 3 4p- Support Group, Sunbury, Ohio, USA.
  • 4 Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA.
  • 5 Department of Internal Medicine, University of New Mexico, Albuquerque, New Mexico, USA.
  • 6 Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA.
  • 7 Stella Maris Clinical Research Institute for Child and Adolescent Neuropsychiatry, Pisa, Italy.
PMID: 26747863 DOI: 10.1136/jmedgenet-2015-103626
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.

Keywords

Clinical genetics; Epilepsy and seizures; Microarray; Neurology.

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