Multipoint linkage analysis and homogeneity tests in 15 Dutch X-linked retinitis pigmentosa families

Linkage analysis and homogeneity tests were carried out in 15 Dutch families segregating X-linked retinitis pigmentosa (xlrp). The study included segregation data for eight polymorphic dna markers from the short arm of the human X chromosome. The results of both multipoint linkage analysis in individual families and heterogeneity analysis support the view that there are only two xlrp loci on the short arm of the human X chromosome, with one locus near the otc gene and one in the vicinity of dxs 255. Furthermore, our data confirm the hypothesis that a tapetal reflex in female carriers can be observed more frequently, if not exclusively, in xlrp families of the rp 3 type.