Trace metals and otolith defects in mocha mice

Mocha mice with pigment anomalies of the coat, eyes, and inner ears also have congenital otolith defects, and they exhibit progressive cochlear degeneration. Mocha mice were first reported to exhibit otolith defects comparable to those of pallid mice. Since manganese supplementation is effective in preventing the otolith defects in pallid mice and in pastel mink, we sought to establish whether or not manganese also might be effective in mocha mice. The otolith defects of mocha mice were prevented or reduced by supplementing the pregnant dams with manganese and/or zinc. The mocha mice also exhibited high perinatal mortality that was not reduced by the supplementary metals. Surviving mocha mice have behavioral anomalies associated with their inner ear defects. Preliminary observations of auditory-evoked brainstem responses and of cochlear degeneration in the mocha mice are discussed.