DNA probes in X-linked retinitis pigmentosa

Informative members of more than twenty families with X-linked retinitis pigmentosa have been sampled by venipuncture and DNA extracted from peripheral blood leucocytes and lymphoblastoid cell lines. X chromosome-specific recombinant DNA probes have been isolated from an X chromosomal genomic DNA library obtained by flow-sorting human chromosomes. These, and similar probes obtained from other laboratories, are being used to identify restriction fragment length polymorphisms in retinitis pigmentosa obligate heterozygotes. By analysis of linkage relationships in the offspring of double heterozygotes, it may be possible to localize the gene(s) responsible for this disorder to a particular subregion of the X-chromosome. Such probes are potentially useful for carrier detection and prenatal diagnosis.