Phenotypes for Fgfr1 MGI:3702996 MGI Mouse

neonatal lethality, complete penetrance ( J:78879 )

• homozygotes die within 24 hrs after birth

abnormal cochlear sensory epithelium morphology ( J:78879 )

• at birth, the three rows of OHCs are disrupted in the lower half of the cochlea, while the sensory epithelium of the upper cochlear half is arranged in patches of variable size rather than as continuous rows

• in the upper cochlear half, the gaps between sensory patches show no signs of differentiation of hair cells or supporting cells

• in contrast, the vestibular sensory epithelium remains unchanged

abnormal cochlear hair cell morphology ( J:78879 )

• at E18.5, homozygotes display variable numbers of OHCs and frequently doublet IHCs, with many HCs appearing shorter than normal

abnormal cochlear hair cell development ( J:78879 )

• at E16.5, homozygotes display no molecular signs of HC specification or differentiation in the gap regions found between sensory patches

• however, the remaining HCs in the sensory patches undergo normal differentiation

absent cochlear outer hair cells ( J:78879 )

• at birth, the third OHC row is absent in the lower half of the cochlea

• in the upper cochlear half, the gaps between the sensory patches display no signs of OHC differentiation

increased cochlear inner hair cell number ( J:78879 )

• at birth, the sensory patches found in the upper cochlear half frequently show doublet IHCs instead of a single continuous IHC row

abnormal orientation of inner hair cell stereociliary bundles ( J:78879 )

• at birth, the sensory patches found in the upper cochlear half frequently show an accumulation of disorientated IHCs at the edges

absent organ of Corti supporting cells ( J:78879 )

• at birth, the sensory patches found in the upper cochlear half frequently show no signs of differentiation of supporting cells