cardiovascular system phenotype

• abnormal cardiovascular system morphology
  • cardiac defects
  (MGI Ref ID J:193237)

mammalian phenotype

• behavior/neurological phenotype
  • Normal - mice do not show circling behavior
  (MGI Ref ID J:193237)

mortality/aging

• premature death
  (MGI Ref ID J:193237)

nervous system phenotype

• abnormal inner hair cell stereociliary bundle morphology
  • the few remaining inner hair cell stereocilia are arranged in a single row rather than 3 rows
  (MGI Ref ID J:193237)
  • outer hair cell stereocilia show loss of structural integrity, particularly those in the outermost row
  (MGI Ref ID J:193237)
  • stereocilia are thicker at the base than in the middle or tips
  (MGI Ref ID J:193237)
  • cell
  (MGI Ref ID J:193237)
  • at 8 weeks of age, many stereocilia appear to collapse against their nearest neighbors, by 16 weeks, stereocilia are elongated and adhere to their neighbors, and at 24 weeks, stereocilia elongate even further and there are fewer stereocilia per inner hair cell
  (MGI Ref ID J:193237)

• abnormal inner hair cell synaptic ribbon morphology
  • inner hair cell ribbon loss is first seen at 8 weeks, preceding the onset of hearing loss, with a 22% reduction at 24 weeks of age
  (MGI Ref ID J:193237)

• decreased inner hair cell stereocilia number
  • number of stereocilia per inner hair cell is reduced to approximately 5 compared to several dozen in wild-type mice at 24 weeks of age, with apparent fusion of the membrane surrounding them
  (MGI Ref ID J:193237)

hearing/vestibular/ear phenotype

• abnormal inner hair cell stereociliary bundle morphology
  • outer hair cell stereocilia show loss of structural integrity, particularly those in the outermost row
  (MGI Ref ID J:193237)
  • the few remaining inner hair cell stereocilia are arranged in a single row rather than 3 rows
  (MGI Ref ID J:193237)
  • at 8 weeks of age, many stereocilia appear to collapse against their nearest neighbors, by 16 weeks, stereocilia are elongated and adhere to their neighbors, and at 24 weeks, stereocilia elongate even further and there are fewer stereocilia per inner hair cell
  (MGI Ref ID J:193237)
  • cell
  (MGI Ref ID J:193237)
  • stereocilia are thicker at the base than in the middle or tips
  (MGI Ref ID J:193237)

• impaired hearing
  • mice do not show hearing loss at 4 and 8 weeks at 12 and 24 kHz, but at 16 and 24 weeks, threshold differences of 35 and 50 dB are seen, indicating severe hearing loss
  (MGI Ref ID J:193237)

• abnormal inner hair cell synaptic ribbon morphology
  • inner hair cell ribbon loss is first seen at 8 weeks, preceding the onset of hearing loss, with a 22% reduction at 24 weeks of age
  (MGI Ref ID J:193237)

• increased or absent threshold for auditory brainstem response
  • mice exhibit higher thresholds indicating that higher sound pressure levels are required to elicit a brainstem response
  (MGI Ref ID J:193237)

• decreased inner hair cell stereocilia number
  • number of stereocilia per inner hair cell is reduced to approximately 5 compared to several dozen in wild-type mice at 24 weeks of age, with apparent fusion of the membrane surrounding them
  (MGI Ref ID J:193237)