HOMOZYGOSITY MAPPING OF AUTOSOMAL RECESSIVE RETINITIS-PIGMENTOSA LOCUS (RP22) ON CHROMOSOME 16P12.1-P12.3

Autosomal recessive retinitis pigmentosa (arRP) is a genetically and c linically heterogeneous and progressive degenerative disorder of the r etina, leading usually to severe visual handicap in adulthood, To date , disease loci/genes have been mapped/identified only in a minority of cases, DNA samples mere collected from 20 large consanguineous Indian families, in which arRP segregated and that were suitable for homozyg osity mapping of the disease locus, After excluding linkage to all kno wn arRP loci, a genome-wide scan was initiated, In two families, homoz ygosity mapping, haplotype analysis, and linkage data mapped the disea se locus (RP22) in an approximately 16-cM region between D16S287 and D 16S420 on the proximal short arm of chromosome 16, No mutation has bee n found by direct sequencing in the gene (CRYM) encoding mu crystallin , which maps in the critical region. (C) 1998 Academic Press.