We have established high-resolution genetic and physical maps and are in the process of identifying and characterizing candidate genes. We have generated both genetic and physical maps, defined the human orthologous region on 6q21, and excluded the Sec63 gene as a candidate for jc. Both loci cause a progressive hearing loss in an overlapping spectrum of inbred strains and both localize to the same chromosomal region and were proposed to be allelic. More interestingly, mdfw and Ahl map to the same chromosomal interval as waltzer, suggesting that mdfw and Ahl are hypomorphic alleles of Cdh23. Dc homozygotes develop a cleft lip and die shortly after birth.
Heterozygotes tend to run in circles and show a white patch of fur on their forehead or belly.
Penetrance, however, is incomplete. It has been suggested that the absence of sensory cells in the vestibule is due to the lack of neuronal innervation. Identification of the Dancer gene may provide insights into the initial steps of vestibule-specific hair cell differentiation. Targeted disruption of mouse Pds provides insights about the inner-ear defects encountered in Pendred syndrome. Correction of deafness in shaker-2 mice by an unconventional myosin in a BAC transgene.