All Phenotypes Myo7a<ewaso> MGI Mouse

hearing/vestibular/ear phenotype ( J:195666 )

N	• mice exhibit normal tympanic membrane, bulla and ossicles

abnormal cochlear basement membrane morphology ( J:195666 )

• at 12 weeks, basilar membrane lack cellular architecture at the mid level due to a lack of sensory or supporting cells unlike wild-type mice

abnormal inner hair cell stereociliary bundle morphology ( J:195666 )

• in some inner hair cell bundles at P5 and 2 weeks

abnormal orientation of inner hair cell stereociliary bundles ( J:195666 )

• disorganized

decreased inner hair cell stereocilia number ( J:195666 )

• progressive with disorganized, fused and elongated stereocilia

fused inner hair cell stereocilia ( J:195666 )

abnormal cochlear outer hair cell morphology ( J:195666 )

• occasionally disorganized at P5 and 2 weeks

decreased outer hair cell stereocilia number ( J:195666 )

• degeneration of whole bundles and within bundles at 4 to 8 weeks

• at 8 weeks, large numbers of outer hair cell bundles are missing at basal and mid levels

cochlear hair cell degeneration ( J:195666 )

• at the basal cochlear region by 8 weeks of age

• profound at 12 weeks

abnormal vestibular hair cell stereociliary bundle morphology ( J:195666 )

• highly irregular with disrupted staircase morphology

• lack of zone of polarity reversal

decreased vestibular hair cell stereocilia number ( J:195666 )

• missing rows of stereocilia

increased or absent threshold for auditory brainstem response ( J:195666 )

• profound from 4 weeks

• however, the increase at 24 weeks is also observed in C57BL/6 wild-type mice

impaired hearing ( J:195666 )