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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID 		Myo7aHdb
headbanger
MGI:3511858
Summary 3 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
 		Myo7aHdb/Myo7aHdb C3HeB/FeJ-Myo7aHdb/Ieg MGI:3511897
ht2
 		Myo7aHdb/Myo7a+ C3HeB/FeJ-Myo7aHdb/Ieg MGI:3511898
ht3
 		Myo7aHdb/Myo7a4626SB involves: BALB/c * 47BS/Rl * C3HeB/FeJ * CBA/Ca MGI:3511901


Genotype
MGI:3511897
hm1
Allelic
Composition		 Myo7aHdb/Myo7aHdb
Genetic
Background		 C3HeB/FeJ-Myo7aHdb/Ieg
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Myo7aHdb mutation (1 available); any Myo7a mutation (118 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype

Stereocilia abnormalities in the Organ of Corti of Myo7aHdb/Myo7a+ and Myo7aHdb/Myo7aHdb mice at P20 and 3 months

behavior/neurological
head bobbing ( J:93998 )
• increased head bobbing observed following weaning compared to heterozygotes
hyperactivity ( J:93998 )
• increased hyperactivity after weaning compared to heterozygotes

hearing/vestibular/ear
decreased inner hair cell stereocilia number ( J:93998 )
• by 3 months, very few inner hair cell stereocilia remained in the apex
fused inner hair cell stereocilia ( J:93998 )
• at P20, apical inner hair cell stereocilia fusion had progressed such that the phenotype resembled the 3-month heterozygote phenotype
decreased outer hair cell stereocilia number ( J:93998 )
• by 3 months, very few outer hair cell stereocilia remained in the apex
increased cochlear nerve compound action potential ( J:93998 )
• 20-23 day old mutants exhibited increased compound action potential from the round window of the cochlea across all frequencies (3-30kHz)

nervous system
decreased inner hair cell stereocilia number ( J:93998 )
• by 3 months, very few inner hair cell stereocilia remained in the apex
fused inner hair cell stereocilia ( J:93998 )
• at P20, apical inner hair cell stereocilia fusion had progressed such that the phenotype resembled the 3-month heterozygote phenotype
decreased outer hair cell stereocilia number ( J:93998 )
• by 3 months, very few outer hair cell stereocilia remained in the apex
increased cochlear nerve compound action potential ( J:93998 )
• 20-23 day old mutants exhibited increased compound action potential from the round window of the cochlea across all frequencies (3-30kHz)




Genotype
MGI:3511898
ht2
Allelic
Composition		 Myo7aHdb/Myo7a+
Genetic
Background		 C3HeB/FeJ-Myo7aHdb/Ieg
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Myo7aHdb mutation (1 available); any Myo7a mutation (118 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype

Stereocilia defects in Myo7aHdb/Myo7a+ mice

behavior/neurological
head bobbing ( J:93998 )
• head bobbing observed following weaning
hyperactivity ( J:93998 )
• appeared hyperactive after weaning

hearing/vestibular/ear
abnormal inner hair cell stereociliary bundle morphology ( J:93998 )
• at E18.5 and P1, apical stereocilia bundles of inner hair cells did not exhibit a height gradient and inner hair cell stereocilia were disorganized
• at P1, the basal inner hair cell stereocilia were disorganized
fused inner hair cell stereocilia ( J:93998 )
• at P20, the inner hair cell stereocilia had more stereocilia sprouting from each cell that had elongated and fused together to form giant stereocilia
abnormal outer hair cell stereociliary bundle morphology ( J:93998 )
• at E18.5 and P1, apical stereocilia bundles of outer hair cells did not exhibit a height gradient
• at P20, the apical outer hair cell bundles formed a more circular pattern
• at P1, basal outer hair cell stereocilia bundles formed a U-shape rather than a V-shape
abnormal vestibular hair cell stereociliary bundle morphology ( J:93998 )
• at P20, utricles displayed bundles of very long and thin rigid stereocilia without the normal staircase arrangement while at 5 months, stereocilia bundles lost their rigidity, were splayed and lay against the utricular surface and showed wispy ends
increased cochlear nerve compound action potential ( J:93998 )
• 20-23 day old mutants displayed a large increase in the compound action potential thresholds from the round window of the cochlea at low frequencies (3-12 kHz)

nervous system
abnormal inner hair cell stereociliary bundle morphology ( J:93998 )
• at E18.5 and P1, apical stereocilia bundles of inner hair cells did not exhibit a height gradient and inner hair cell stereocilia were disorganized
• at P1, the basal inner hair cell stereocilia were disorganized
fused inner hair cell stereocilia ( J:93998 )
• at P20, the inner hair cell stereocilia had more stereocilia sprouting from each cell that had elongated and fused together to form giant stereocilia
abnormal outer hair cell stereociliary bundle morphology ( J:93998 )
• at E18.5 and P1, apical stereocilia bundles of outer hair cells did not exhibit a height gradient
• at P20, the apical outer hair cell bundles formed a more circular pattern
• at P1, basal outer hair cell stereocilia bundles formed a U-shape rather than a V-shape
abnormal vestibular hair cell stereociliary bundle morphology ( J:93998 )
• at P20, utricles displayed bundles of very long and thin rigid stereocilia without the normal staircase arrangement while at 5 months, stereocilia bundles lost their rigidity, were splayed and lay against the utricular surface and showed wispy ends
increased cochlear nerve compound action potential ( J:93998 )
• 20-23 day old mutants displayed a large increase in the compound action potential thresholds from the round window of the cochlea at low frequencies (3-12 kHz)




Genotype
MGI:3511901
ht3
Allelic
Composition		 Myo7aHdb/Myo7a4626SB
Genetic
Background		 involves: BALB/c * 47BS/Rl * C3HeB/FeJ * CBA/Ca
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Myo7a4626SB mutation (3 available); any Myo7a mutation (118 available)
Myo7aHdb mutation (1 available); any Myo7a mutation (118 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype

Cochlear hair cell abnormalities in Myo7aHdb/Myo7a+, Myo7aHdb/Myo7a+ Myo7a4626SB/Myo7a+, and Myo7ash1/Myo7ash1 mice

hearing/vestibular/ear
abnormal inner hair cell stereociliary bundle morphology ( J:93998 )
• apical stereocilia bundles of inner hair cells appeared more disorganized than in Hdb heterozygotes but less than in Hdb homozygotes
fused inner hair cell stereocilia ( J:93998 )
• inner hair cell fusion was significantly reduced compared to that seen in Hdb homozygotes but not when compared to Hdb heterozygotes
abnormal outer hair cell stereociliary bundle morphology ( J:93998 )
• apical stereocilia bundles of outer hair cells appeared more disorganized than in Hdb heterozygotes but less than in Hdb homozygotes

nervous system
abnormal inner hair cell stereociliary bundle morphology ( J:93998 )
• apical stereocilia bundles of inner hair cells appeared more disorganized than in Hdb heterozygotes but less than in Hdb homozygotes
fused inner hair cell stereocilia ( J:93998 )
• inner hair cell fusion was significantly reduced compared to that seen in Hdb homozygotes but not when compared to Hdb heterozygotes
abnormal outer hair cell stereociliary bundle morphology ( J:93998 )
• apical stereocilia bundles of outer hair cells appeared more disorganized than in Hdb heterozygotes but less than in Hdb homozygotes

Mouse Models of Human Disease
 DO ID OMIM ID(s) Ref(s)
Usher syndrome type 1 DOID:0110826 OMIM:276900
 J:93998




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11/12/2024
MGI 6.24 		The Jackson Laboratory