Hearing loss in Varitint-waddler-J (VaJ) mice is of mixed origin with both cochleo-saccular
and neuroepithelial components. Both VaJ/VaJ and VaJ/+ mutants show impaired cochlear
function, but the homozygotes are more severely affected than heterozygotes. Neither group
have any detectable compound action potential. Cochlear microphonics are only seen in
half of the heterozygotes, at a reduced amplitude and raised threshold, and are not detected
in any homozygotes. Summating potentials (SP) responses are seen in most of the …