Phenotypes associated with this allele

• Allele Symbol: Wt
• Allele Name: waltzer-type
• Allele ID: MGI:1861234
• Summary: 2 genotypes

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Wt/Wt	Not Specified	MGI:3716288
ht2	Wt/Wt^+	Not Specified	MGI:3716320

Genotype
MGI:3716288

hm1

• Allelic Composition: Wt/Wt
• Genetic Background: Not Specified

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

mortality/aging

embryonic lethality during organogenesis, incomplete penetrance ( J:122950 )

• in litters of >11 days gestation, numerous degenerating embryos are observed

embryo

abnormal embryo development ( J:122950 )

• ~25% of embryos are abnormal at 10.5-11 days of gestation

• in some embryos, mesodermal and endodermal tissues show degeneration, particularly at later stages

embryonic growth retardation ( J:122950 )

• developmental retardation is evident in brain, in optic and otic vesicles

decreased embryo size ( J:122950 )

• smaller than embryonic littermates

abnormal neural tube morphology ( J:122950 )

• earlier than 10.5 days of gestation, abnormal embryos show elevated pyknotic nuclei in the neural tube

growth/size/body

embryonic growth retardation ( J:122950 )

• developmental retardation is evident in brain, in optic and otic vesicles

decreased embryo size ( J:122950 )

• smaller than embryonic littermates

hearing/vestibular/ear

abnormal inner ear development ( J:122950 )

• differentiation into vestibular and cochlear structures of ear fails to occur

abnormal otic vesicle development ( J:122950 )

• otic vesicles are retarded in all homozygotes

• at 9.5-10.5 days gestation, auditory vesicles show only ~50% as many mitotic figures as normal embryos

absent endolymphatic duct ( J:122950 )

• embryos lack ducts

nervous system

abnormal neural tube morphology ( J:122950 )

• earlier than 10.5 days of gestation, abnormal embryos show elevated pyknotic nuclei in the neural tube

abnormal brain morphology ( J:122950 )

• at 10.5-11 days of gestation, embryos have abnormal brains with varying degrees of degeneration; brains are distorted and either collapsed or inflated in all mutant embryos

abnormal fourth ventricle morphology ( J:122950 )

• in some embryos at 10.5 days, fourth ventricle is open

abnormal cochlear ganglion morphology ( J:122950 )

• smaller than controls, occasionally with pyknotic nuclei

abnormal geniculate ganglion morphology ( J:122950 )

• smaller than controls, occasionally with pyknotic nuclei

spinal cord degeneration ( J:122950 )

• degeneration of spinal cord is observed at 10.5-11 days of gestation

taste/olfaction

abnormal nasal placode morphology ( J:122950 )

• placodes form and in some embryos become indented, in contrast to the deeply indented ducts observed in littermates

vision/eye

abnormal optic placode morphology ( J:122950 )

• lens placodes are absent or not indented compared to normal littermates at 9.5-10.5 days gestation

absent optic placodes ( J:122950 )

cellular

abnormal mitosis ( J:122950 )

• mitotic divisions in the developing ear are fewer in mutants relative to wild-type (~45 for mutants vs 245 for controls)

respiratory system

abnormal nasal placode morphology ( J:122950 )

• placodes form and in some embryos become indented, in contrast to the deeply indented ducts observed in littermates

craniofacial

abnormal nasal placode morphology ( J:122950 )

• placodes form and in some embryos become indented, in contrast to the deeply indented ducts observed in littermates

Genotype
MGI:3716320

ht2

• Allelic Composition: Wt/Wt⁺
• Genetic Background: Not Specified

behavior/neurological

abnormal emotion/affect behavior ( J:30696 )

• mildly-affected mutants may display nervousness

increased anxiety-related response ( J:304 )

• severely affected mice become hysterical during swim test, and will drown if not rescued

impaired swimming ( J:304 )

• less severely affected mice when dropped in water regain the surface and swim in fairly straight line, whereas severely affected mice will swim wildly in circles, often from top to bottom of tank, without emerging to surface, and must be rescued

head bobbing ( J:304 )

• head shaking in vertical direction is observed occasionally

retropulsion ( J:304 )

• mice have tendency to move backwards, often for distance of several feet, when exploring or attempting to escape at 3-4 weeks of age

circling ( J:304 , J:30696 )

• 13% of offspring from heterozygous carrier and wild-type crosses display waltzing behavior at 3-4 weeks (J:304)

• mutation shows incomplete penetrance and variable expression; strong expression leads to violent circling (J:30696)

bidirectional circling ( J:304 )

• observed usually starting at 3 weeks of age

abnormal maternal nurturing ( J:304 , J:30696 )

♀ • females fail to rear their offspring (J:304)

♀ • often, females do not tend their litters well (J:30696)

hearing/vestibular/ear

hearing/vestibular/ear phenotype ( J:304 , J:30696 )

N • no abnormalities in morphology of cochlea have been noted, and animals can hear (J:304)

N • ear structures, outside of the canals, appear to be normal in mutants (J:304)

N • animals are not deaf (J:30696)

abnormal semicircular canal morphology ( J:304 )

• shortening or reduced diameter of one or more canals is observed in some embryos at 13-16 days of gestation

• abnormalities range from slight size reduction to canal absence distal to ampulla at 3-4 weeks

• severely affected mice where canals on both sides are affected exhibit active waltzing behavior and severely impaired swimming, although some mice not displaying circling behavior have severely abnormal canals; unilateral defects are not conducive to circling behavior

abnormal lateral semicircular canal morphology ( J:304 )

• lateral canal is affected in mice with abnormal labyrinths at 3-4 weeks; in more severely affected animals the canal can end abruptly

decreased lateral semicircular canal size ( J:304 )

• more severely affected canals are attenuated to a narrow lumenless strand

abnormal posterior semicircular canal morphology ( J:304 )

• lateral canal is affected in mice with abnormal labyrinths; often, canal is missing between crus commune and utricle

absent semicircular canals ( J:304 )

• in some embryos at 13-16 days of gestation, one canal or more is missing

abnormal vestibular labyrinth morphology ( J:304 )

• 48% of offspring from heterozygotes mated with wild-type mice exhibit abnormalities of the vestibular portion of the labyrinth at 3-4 weeks

• severely affected mice exhibit active waltzing behavior; severely impaired swimming is more common with severe labyrinth defects

reproductive system

reproductive system phenotype ( J:304 )

N • male and females are excellent breeders