Viability and breeding ability are somewhat less than normal. Homozygotes show the typical circling, head-tossing, deafness, and hyperactivity of the circling mutants. Most of them are deaf from the beginning. Abnormalities of the inner ear include degeneration of the organ of Corti, spiral ganglion, stria vascularis, and saccular macula. Double heterozygotes with shaker-1 (Cdh23^v/+ Myo7^ash1/+) are deaf beginning at 3 to 6 months. They have changes similar to those of the homozygotes in the organ of Corti, stria vascularis, and spiral ganglion, but less severe and with much later onset (J:13130)(J:15164).