We have begun a study of the hereditary Waardenburg syndrome,which in its varying phenotype includes a hearing impairment. Blood is now being taken from family members with the Waardenburg syndrome for extraction of DNA and for transformation of the lymphocytes to establish immortal cell lines. Linkage studies are in progress. Among cell lines under study for the Waardenburg syndrome is included cells with a chromosome inversion on the long arm of chromosome 2, from a child with a de novo appearance of the Waardenburg syndrome. Among techniques to be used is in situ hybridization, using fluorescent DNA probes and laser confocal microscopy techniques. We are continuing our study of the hereditary deafness in the Bronx Waltzer, a strain of mouse with the mutant gene by that is autosomal, recessive, with full penetrance. We have initiated mapping experiments in collaboration with Dr. B. A. Taylor, the Jackson Laboratory, Bar Harbor, Maine. Moreover, we have found that after 3 generations of breeding to an FVB background of mice, Bronx Waltzers show a loss of inner hair cells, implying that such loss in the original Bronx Waltzer strain is likely due to a single gene. Total RNA was prepared from the chick membranous labyrinth, including the basilar papilla, the vascular stria and supporting cells. The RNA was amplified using PCR with primers made to be specific for 2 conserved regions of the potassium channel family. Results indicate that 2 major members of the potassium channel family (CBK1 and CBK2) are present in the.membranous labyrinth. Moreover, a new, third class of potassium channels has been tentatively identified to be present in both the basilar papilla and in the brain of the chick. These findings are being followed up. Using molecular biology techniques including amplification using PCR we have found several putatative new members of the G protein-coupled receptor family of proteins in tissue from the cochlea of mice and of guinea pigs. In our search for such monoclonal antibodies that can serve as markers in the cochlea, we are using a newly described technique (W. D. Huse, et al., 1990) that includes the making of libraries of Fab fragments in E. coli.
