This semi-dominant craniofacial mutation causes a short nose, round skull, wide-set eyes, and severe hearing impairment, along with an increased propensity for otitis media.Read More +
Round nose heterozygotes have a short nose, round skull, and wide-set eyes. Skull measurements show shorter maxillae, longer skull length, increased intercanthal distance, increased ratio of skull height to length and decreased ratio of skull length to width, with these measurements reaching significance in males but only showing comparable trends not reaching significance in females. The ratio of skull to body areal bone mineral density is also significantly higher in heterozygous males but not in females. Click-box testing and auditory brainstem response threshold testing both found severe hearing impairment and pathology screens found otitis media in three of nine heterozygotes. Females may have smaller litter sizes than normal. Some heterozygotes have misaligned jaws so require trimming of the teeth to address the malocclusion. This mutation is sensitive to genetic background. Attempts to map this mutation failed to produce any pups with the phenotype in the F1 hybrid population when outcrossed to A/J (0/37 pups), BALB/cByJ (0/67 pups), CAST/EiJ (0/7 pups), CBA/CaJ (0/32 pups), or FVB/NJ (0/7 pups). When outcrossed to C3H/HeSnJ the phenotype appears in some F1 hybrids and in pups from F1 x C57BL/6J backcrosses.
The semi-dominant round nose mutation was identified in the progeny of an ENU treated C57BL/6J male generated by the neuroscience mutagenesis program at The Jackson Laboratory. This mutation has been maintained coisogenic on the C57BL/6J background. Sperm was cryopreserved from heterozygous males at generations N1F12 through N1F14.
Females may have smaller litter sizes than normal. Some heterozygotes have misaligned jaws so require trimming of the teeth to address the malocclusion.
When using the round nose mouse strain in a publication, please cite the originating article(s) and include JAX stock #004378 in your Materials and Methods section.