title: Superior Canal Dehiscence Syndrome Affecting 3 Families.
abstract: Superior canal dehiscence syndrome (SCDS) is an increasingly recognized cause of hearing loss and vestibular symptoms, but the etiology of this condition remains unknown.
  
  
  
  To describe 7 cases of SCDS across 3 families.
  
  
  
  This retrospective case series included 7 patients from 3 different families treated at a neurotology clinic at a tertiary academic medical center from 2010 to 2014. Patients were referred by other otolaryngologists or were self-referred. Each patient demonstrated unilateral or bilateral SCDS or near dehiscence.
  
  
  
  Clinical evaluation involved body mass index calculation, audiometry, cervical vestibular evoked myogenic potential testing, electrocochleography, and multiplanar computed tomographic (CT) scan of the temporal bones. Zygosity testing was performed on twin siblings.
  
  
  
  The diagnosis of SCDS was made if bone was absent over the superior semicircular canal on 2 consecutive CT images, in addition to 1 physiologic sign consistent with labyrinthine dehiscence. Near dehiscence was defined as absent bone on only 1 CT image but with symptoms and at least 1 physiologic sign of labyrinthine dehiscence.
  
  
  
  A total of 7 patients (5 female and 2 male; age range, 8-49 years) from 3 families underwent evaluation. Family A consisted of 3 adult first-degree relatives, of whom 2 were diagnosed with SCDS and 1 with near dehiscence. Family B included a mother and her child, both of whom were diagnosed with unilateral SCDS. Family C consisted of adult monozygotic twins, each of whom was diagnosed with unilateral SCDS. For all cases, dehiscence was located at the arcuate eminence. Obesity alone did not explain the occurrence of SCDS because 5 of the 7 cases had a body mass index (calculated as weight in kilograms divided by height in meters squared) less than 30.0.
  
  
  
  Superior canal dehiscence syndrome is a rare, often unrecognized condition. This report of 3 multiplex families with SCDS provides evidence in support of a potential genetic contribution to the etiology. Symptomatic first-degree relatives of patients diagnosed with SCDS should be offered evaluation to improve detection of this disorder.
authors.affiliation: Division of Otology-Neurotology, Department of Otolaryngology-Head and Neck Surgery, University of Michigan Health System, Ann Arbor.
authors.forename: Katherine D
authors.initials: KD
authors.lastname: Heidenreich
authors.affiliation: Division of Otology-Neurotology, Department of Otolaryngology-Head and Neck Surgery, University of Michigan Health System, Ann Arbor.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Kileny
authors.affiliation: Division of Otology-Neurotology, Department of Otolaryngology-Head and Neck Surgery, University of Michigan Health System, Ann Arbor.
authors.forename: Sameer
authors.initials: S
authors.lastname: Ahmed
authors.affiliation: Division of Otology-Neurotology, Department of Otolaryngology-Head and Neck Surgery, University of Michigan Health System, Ann Arbor.
authors.forename: Hussam K
authors.initials: HK
authors.lastname: El-Kashlan
authors.affiliation: Division of Pediatric Otolaryngology, Department of Otolaryngology-Head and Neck Surgery, University of Michigan Health System, Ann Arbor.
authors.forename: Tori L
authors.initials: TL
authors.lastname: Melendez
authors.affiliation: Division of Otology-Neurotology, Department of Otolaryngology-Head and Neck Surgery, University of Michigan Health System, Ann Arbor.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Basura
authors.affiliation: Division of Pediatric Otolaryngology, Department of Otolaryngology-Head and Neck Surgery, University of Michigan Health System, Ann Arbor.
authors.forename: Marci M
authors.initials: MM
authors.lastname: Lesperance
mesh_terms: D000293:Adolescent; D000328:Adult; D001300:Audiometry, Evoked Response; D015992:Body Mass Index; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007759:Labyrinth Diseases / Q000175:diagnosis* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012665:Semicircular Canals / Q000002:abnormalities*; D013577:Syndrome; D013701:Temporal Bone / Q000002:abnormalities*; D014057:Tomography, X-Ray Computed; D058585:Vestibular Evoked Myogenic Potentials