Phenotypes Associated with This Genotype

Genotype
MGI:3697649

• Allelic Composition: Efnb2^tm1.1Henk/Efnb2⁺
• Genetic Background: involves: 129 * CD-1

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

behavior/neurological

head bobbing ( J:116671 )

• on a ~87.5% CD-1 background (3 backcross generations), 13.5% of adult heterozygotes exhibit rapid head bobbing

circling ( J:116671 )

• on a ~87.5% CD-1 background (3 backcross generations), 13.5% of adult heterozygotes exhibit continuous, hyperactive circling

• waltzing is first apparent at ~P10, i.e. when locomotion begins

• Background Sensitivity: on a 129 or C57BL/6 background, adult heterozygotes appear normal with no vestibular dysfunction

hearing/vestibular/ear

decreased posterior semicircular canal size ( J:116671 )

• on a CD-1 background, adult heterozygotes show a >50% decrease in the mean cross-sectional area of posterior vertical canals relative to wild-type

decreased superior semicircular canal size ( J:116671 )

• on a CD-1 background, adult heterozygotes show a >50% decrease in the mean cross-sectional area of anterior vertical canals relative to wild-type

small endolymphatic duct ( J:116671 )

• on a CD-1 background, endolymph-filled membranous ducts are severely reduced

abnormal endolymph physiology ( J:116671 )

• on a CD-1 background, reduced endolymph-filled lumens lead to a significant reduction in the flow of endolymph fluid through the semicircular canals