MAPPING OF THE ROD PHOTORECEPTOR ABC TRANSPORTER (ABCR) TO 1P21-P22.1AND IDENTIFICATION OF NOVEL MUTATIONS IN STARGARDTS-DISEASE

Using a bovine rod photoreceptor cell-specific ATP-binding cassette (A BC) transporter cDNA we have cloned the full-length transcript of the homologous human gene and demonstrate that it is identical to the phot oreceptor cell-specific ABC transporter (ABCR) recently shown to be mu tated in Stargardt's disease. By fluorescence in situ hybridization we have mapped the ABCR gene to chromosomal band 1p21-p22.1. Mutational analysis of part of the gene in 15 Stargardt's disease patients has id entified four disease-causing mutations, of which two represent potent ial null alleles. This brings the total number of independently identi fied mutations to 23, providing further evidence that the human ABCR g ene is associated with Stargardt's disease.