Phenotypes Associated with This Genotype

Genotype
MGI:8272181

• Allelic Composition: Grm6^em#Mrho/Grm6^em#Mrho
• Genetic Background: C57BL/6J-Grm6^em#Mrho

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

vision/eye

decreased b-wave amplitude ( J:371980 )

• rod-dominated (scotopic) electroretinograms (ERGs) show no appreciable b-wave

abnormal eye electrophysiology ( J:371980 )

• retinal ganglion cells (RGCs) display no light-evoked responses, indicating complete ON retinal pathway suppression

• voltage-clamp recordings show absent light-driven excitation and inhibition in ON sustained alpha (ONalpha) RGCs

• current-clamp recordings to measure the resting membrane potential of ONalpha RGCs show that RGCs are hyperpolarized relative to wild-type or heterozygous RGCs

• ONalpha RGCs exhibit reduced spiking ability in response to depolarizing current injections

• OFF-sustained (OFF-sus) alpha RGCs fail to suppress spiking during dim light flashes applied from darkness and show a reduced peak spike rate at light offset, with RGCs showing mild improvement at moderate light conditions and normal spike suppression under bright conditions, indicating that OFF-sus RGCs show the most severe impairments in their ability to fire properly at dim-light levels

• OFF-sus alpha RGCs are almost insensitive to contrast at both moderate and bright light luminance levels and thus incapable of contrast encoding, with reduced slope of the contrast response curve

• in summary, lack of ON pathway input disrupts the contrast sensitivity of OFF-sus RGCs

abnormal retinal bipolar cell electrophysiology ( J:371980 )

• dendrites of rod bipolar cells show no response to a light flash

decreased visual acuity ( J:371980 )

• in the optomotor response assay, mice exhibit reduced visual acuity

abnormal visual contrast sensitivity ( J:371980 )

• in the optomotor response assay, mice exhibit reduced contrast sensitivity

nyctalopia ( J:371980 )

Mouse Models of Human Disease		DO ID	OMIM ID(s)	Ref(s)
congenital stationary night blindness 1B		DOID:0110865	OMIM:257270	J:371980