BELGIAN WATERSLAGER CANARIES ARE AFFLICTED BY SCHEIBE-LIKE DYSPLASIA

Behavioral investigations of Belgian Waterslager canaries (BWCs) have demonstrated a congenital hearing impairment that primarily affects hi gh frequencies. Research into the surface anatomy of the basilar papil la of these birds has pointed to the hair cells as the site of the les ion. Given that the basilar papilla and the vestibular organs bath dev elop from the otocyst, we were interested in ascertaining whether the vestibular sensory epithelia also displayed abnormal hair cells. The i nner ear of adult BWCs was examined by scanning electron microscopy. A s expected, hair cells in the basilar papilla of BWCs were abnormal. A s for the vestibular parenchyma, abnormal hair cells were detected in only one structure: the sacculus. Morphological abnormalities of the c ochlea and sacculus are pathognomonic signs of Scheibe's dysplasia, th e most common inner ear defect associated with congenital hearing loss . Our results suggest that BWCs are afflicted by this genetic disorder .