White noise: Pigment-associated deafness

摘要

Congenital deafness associated with white pigmentation has become a widely recognised disorder in dogs and cats, described in the dog at least as early as 1896 (Strain, 1996). The same condition is recognised in a variety of other domestic species, including pigs, cattle and horses. In most dog and cat breeds, the deafness is of the cochleosaccular or Schiebe type, where a sequence is followed of degeneration of the stria vascularis, death of organ of Corti hair cells, collapse of Reissner’s membrane and the cochlear duct and secondary loss of spiral ganglion cells, whose axons form the auditory branch of the eighth cranial nerve (Coppens et al., 2003 A.G. Coppens, I. Salmon, C.W. Heizmann, R. Kiss and L. Poncelet, Postnatal maturation of the dog stria vascularis – an immunohistochemical study. Anatomical Record Part A, 270A (2003), pp. 82–92. Coppens et al., 2003). Deafness that is not associated with genes for white is of the neuroepithelial type, where hair cells degenerate without preceding injury to the stria; this form is much less common.