Phenotypes Associated with This Genotype

Genotype
MGI:6323255

• Allelic Composition: Slc7a8^tm1Geno/Slc7a8^tm1Geno
• Genetic Background: involves: 129 * C57BL/6J

• ♀: phenotype observed in females
• ♂: phenotype observed in males
• N: normal phenotype

behavior/neurological

impaired coordination ( J:256844 )

• mice show a reduction in latency in the accelerating rotarod

• mice show poorer performance than wild-type mice at time of exposure to shock on the treadmill test

• however, learning and memory are not affected in mutants

hearing/vestibular/ear

cochlear hair cell degeneration ( J:256844 )

• 3 of 6 mice show complete loss of hair cells and flat epithelia in the basal turns of the cochlea

abnormal spiral ligament morphology ( J:256844 )

• cells in the spiral ligament are less densely packed

abnormal spiral ligament fibrocyte morphology ( J:256844 )

• the number of fibrocytes in the spiral ligament is decreased by 2/3

• mice with severe hearing loss show 30% less fibrocyte number in the spinal ligament

abnormal strial basal cell morphology ( J:256844 )

• actin fibers in the basal cells of the stria vascularis are decreased 50% in the base of the cochlea

abnormal auditory brainstem response waveform shape ( J:256844 )

• ABR waves in response to click stimuli show increased latency and decreased amplitude of wave I, but similar II-IV interpeak latency, indicating hypoacusis of peripheral origin without affecting the central auditory pathway

increased or absent threshold for auditory brainstem response ( J:256844 )

• 4 to 6 month old mice show higher auditory brainstem response (ABR) thresholds in response to click stimulus, with hearing loss affecting the highest frequencies tested (10, 28, and 40 kHz)

impaired hearing ( J:256844 )

• at 4-6 months of age, 37.5% of mice show severe hearing loss while 255 show mild hearing loss

• at 7-13 months of age, 50% of mice show severe hypoacusis and hearing loss spreads to lower frequencies with age and 43% of mice develop mild hearing loss

• Background Sensitivity: hearing loss penetrance is lower on the mixed background than on a congenic C57BL/6J background

nervous system

cochlear hair cell degeneration ( J:256844 )

• 3 of 6 mice show complete loss of hair cells and flat epithelia in the basal turns of the cochlea

cochlear ganglion degeneration ( J:256844 )

• about 50% loss of cells in the spiral ganglia, especially in the basal regions of the cochlea, in 4 to 7 month old mice

decreased prepulse inhibition ( J:256844 )

• mice exhibit an impairment in the pre-pulse inhibition of acoustic startle response, with the response to a 120 dB single-pulse reduced, indicating a hearing impairment

skeleton

abnormal spiral ligament morphology ( J:256844 )

• cells in the spiral ligament are less densely packed

abnormal spiral ligament fibrocyte morphology ( J:256844 )

• the number of fibrocytes in the spiral ligament is decreased by 2/3

• mice with severe hearing loss show 30% less fibrocyte number in the spinal ligament

homeostasis/metabolism

homeostasis/metabolism phenotype ( J:256844 )

N • mice show no differences in corticosterone levels at either basal conditions or under restraint stress indicating a normal stress response

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
sensorineural hearing loss		DOID:10003		J:256844