Phenotypes Associated with This Genotype

Genotype
MGI:2673276

• Allelic Composition: Six1^tm1Mair/Six1⁺
• Genetic Background: either: (involves: 129) or (involves: 129 * C57BL/6)

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

hearing/vestibular/ear

abnormal cochlea morphology ( J:84974 )

• at E16.5, 4 of 22 heterozygous ears (in 3 of 11 embryos) display slightly shortened cochlea by latex paintfilling

abnormal middle ear morphology ( J:84974 )

• the middle ear space is small and partially filled with loose connective tissue, probably due to secondary inflammation

absent stapedial artery ( J:84974 )

• stapedial arteries are absent in 4 cases from 3 heterozygous animals

abnormal stapes morphology ( J:84974 )

• although the footplates of the stapes are seated in the oval window, the stapes has a small lumen

abnormal tympanic membrane morphology ( J:84974 )

increased or absent threshold for auditory brainstem response ( J:84974 )

• on a 129/Sv background, 8 of 13 heterozygotes show severe bilateral hearing loss (threshold shifted by 50 dB between 15 and 32 kHz), 2 of 13 mice show mild bilateral hearing loss (threshold shifted by 20 dB), whereas the remaining 3 mice have normal hearing in the right ears and >70 dB loss in the left ears

conductive hearing loss ( J:84974 )

• most heterozygotes exhibit some degree of conductive hearing loss; variable among mice and ears

• all affected heterozygotes show a failure of the middle ear ossicles to complete a sound transmission path from the tympanum to the oval window

unilateral deafness ( J:84974 )

• on a 129/Sv background, 3 of 13 heterozygotes display normal hearing in the right ears and >70 dB loss in the left ears

nervous system

abnormal facial nerve morphology ( J:84974 )

• in heterozygotes, the VIIth nerve passes abnormally close to the oval window and the stapes or fills up the middle ear space near the oval window

cardiovascular system

absent stapedial artery ( J:84974 )

• stapedial arteries are absent in 4 cases from 3 heterozygous animals

craniofacial

abnormal stapes morphology ( J:84974 )

• although the footplates of the stapes are seated in the oval window, the stapes has a small lumen

skeleton

abnormal stapes morphology ( J:84974 )

• although the footplates of the stapes are seated in the oval window, the stapes has a small lumen