Phenotypes associated with this allele

• Allele Symbol: Cachd1^em1Kjn
• Allele Name: endonuclease-mediated mutation 1, Kenneth R Johnson
• Allele ID: MGI:6827308
• Summary: 1 genotype

Jump to	Allelic Composition	Genetic Background	Genotype ID
hm1	Cachd1^em1Kjn/Cachd1^em1Kjn	C57BL/6J-Cachd1^em1Kjn/KjnJ	MGI:6828613

Genotype
MGI:6828613

hm1

• Allelic Composition: Cachd1^em1Kjn/Cachd1^em1Kjn
• Genetic Background: C57BL/6J-Cachd1^em1Kjn/KjnJ

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

behavior/neurological

head tilt ( J:314293 )

circling ( J:314293 )

• incomplete penetrance, with overt circling and head tilting found in only approximately 45% of homozygotes

nervous system

decreased cochlear outer hair cell number ( J:314293 )

craniofacial

small temporal bone ( J:314293 )

hearing/vestibular/ear

abnormal inner ear morphology ( J:314293 )

• there are many architectural abnormalities of the inner ear, including the dimension or absence of the boney interscalar septum between the lower cochlear basal and apical turn, and the cochlear outer hair cells of the basal turn are almost entirely absent, although inner hair cells are less impacted as assessed at E15.5 and birth

abnormal inner ear development ( J:314293 )

abnormal membranous labyrinth morphology ( J:314293 )

• Variable dilation of the membranous labyrinth at E15.5 and birth, including enlarged endolymphatic duct, utricle, saccule, and cochlear duct, but not the endolymphatic sac

abnormal scala media morphology ( J:314293 )

abnormal organ of Corti morphology ( J:314293 )

• highly atrophic at the basal turn where there is near absence of outer hair cells, but reasonably normal inner hair cells

decreased cochlear outer hair cell number ( J:314293 )

abnormal tectorial membrane morphology ( J:314293 )

• assessed at birth, can be absent, displaced or near normal

abnormal utricle morphology ( J:314293 )

abnormal vestibular saccule morphology ( J:314293 )

dilated endolymphatic duct ( J:314293 )

decreased otolith number ( J:314293 )

• variable deficiencies of otoconia in both the saccule and utricle

abnormal endolymph physiology ( J:314293 )

• cochlear fluid spaces are laterally expanded with several anatomical components displaced including the organ of Corti and Reissner's membrane

abnormal cochlear endolymph ionic homeostasis ( J:314293 )

• generally significantly increased endolymph calcium levels, but this varies widely between individual homozygotes

decreased endocochlear potential ( J:314293 )

• decreased to under 20 mV in approximately half of the homozygotes, but very variable in the population of homozygotes

increased endolymph production ( J:314293 )

increased or absent threshold for auditory brainstem response ( J:314293 )

• between 5-12 weeks of age the average increase in ABR threshold is 40-50 dB, this is variable and not fully penetrant, but those mice displaying a vestibular phenotype usually have elevated ABR thresholds, and the hearing loss does not progress with age from 1 to 6 months of age

abnormal distortion product otoacoustic emission ( J:314293 )

• significantly decreased DPOAE

skeleton

small temporal bone ( J:314293 )