LOCALIZATION OF THE GENE FOR PROGRESSIVE BIFOCAL CHORIORETINAL ATROPHY (PBCRA) TO CHROMOSOME 6Q

Progressive bifocal chorioretinal atrophy (PBCRA) is a rare, autosomal dominant congenital chorioretinal dystrophy. We have performed geneti c linkage analysis on a five-generation British pedigree. Two-point li nkage analysis showed significant linkage with nine microsatellite mar ker loci mapping to chromosome 6q. Multipoint analysis gave a maximum lod score of 11.8 (theta = 0.05) between D6S249 and D6S283. This regio n overlaps with that to which the gene for North Carolina macular dyst rophy (MCDR1) has been assigned. However, given the range of differenc es in phenotype between these two retinal disorders, it is likely that different mutation mechanisms are responsible for each disease.