Detection of a megabase deletion in a patient with branchio-oto-renal syndrome (BOR) and tricho-rhino-phalangeal syndrome (TRPS): implications for mapping and cloning the BOR gene.

Genetic linkage analysis has previously mapped the locus for the autosomal dominant disorder branchio-oto-renal syndrome (BOR) to the pericentric region of chromosome 8q. A YAC contig spanning the putative BOR region, from D8S543 to D8S541, was constructed and confirmed by sequence-tagged site content mapping using microsatellite markers and by DNA hybridization analysis. YACs spanning the BOR interval were used as fluorescence in situ hybridization probes on a cell line from a patient with BO and tricho-rhino-phalangeal syndrome I that involves a chromosome 8q rearrangement. In addition to the cytogenetically defined direct insertion of material from 8q13.3-q21.13 into 8q24.11, a previously unidentified deletion of just under one megabase was found in 8q13.3. These data narrowed the most likely location of the BOR gene to a region corresponding to the proximal two-thirds of YAC 869E10 between D8S543 and D8S279.