Phenotypes Associated with This Genotype

Genotype
MGI:3703706

cn5

• Allelic Composition: Tbx1^tm2.1Bem/Tbx1^tm2.2Bem; Tg(Pax2-cre)1Akg/0
• Genetic Background: involves: 129 * C57BL/6 * SJL

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

hearing/vestibular/ear

small otic vesicle ( J:109536 )

• at E10.5

otic vesicle hypoplasia ( J:109536 )

• early otic vesicle development is normal; however, the structure is hypoplastic at E10.5

• in contrast, periotic mesenchyme development appears normal

abnormal inner ear morphology ( J:109536 )

• at E17.5, 12 of 16 mutant ears show complete failure of inner ear development while the remaining appear completely normal

• in contrast, formation of the otic capsule and development of middle ear ossicles and pinnae is clearly normal at E17.5 and in adulthood

absent cochlea ( J:109536 )

• in 12 of 16 mutant inner ears

absent semicircular canals ( J:109536 )

• in 12 of 16 mutant inner ears

absent inner ear vestibule ( J:109536 )

• in 12 of 16 mutant inner ears

absent inner ear ( J:109536 )

• at E17.5, 6 of 8 mutants show complete aplasia of inner ear sensory organs

inner ear hypoplasia ( J:109536 )

• at E17.5, 6 of 8 mutant embryos display a severely hypoplastic inner ear

• severe hypoplasia is bilateral and present in 12/16 mutant ears

• at E17.5, the inner ear persists in a rudimentary otic vesicle stage

increased or absent threshold for auditory brainstem response ( J:109536 )

• 3 of 5 adults exhibit no hearing on either the left or right side, as determined by auditory brainstem response testing

• the remaining two adults display normal hearing, consistent with the incomplete penetrance of the inner ear phenotype noted at E17.5

sensorineural hearing loss ( J:109536 )

• in 3 of 5 adult mutants

nervous system

abnormal vestibulocochlear ganglion morphology ( J:109536 )

• at E10.5, a smaller otic vesicle is surrounded by an expanded cochleovestibular ganglion

• at E11.5, the cochleovestibular ganglion is duplicated around the otic vesicle anterior-posterior midline

embryo

embryo phenotype ( J:109536 )

N • at E10.5, mutants show normal invagination of the pharyngeal endoderm to form the future tubotympanic recess

craniofacial

craniofacial phenotype ( J:109536 )

N • mutants survive in normal Mendelian ratios through adulthood and show normal craniofacial bone development at E17.5