Figure 1. Pedigree drawings of families PKRP161 and PKRP183 with haplotyes of five adjacent chromosomes 4p microsatellite markers and variations identified in PDE6β. Single base changes: c.1655G>A and c.1160C>T were identified in PKRP161 and PKRP183, respectively and segregate with the disease phenotype in their respective families. Squares: males; circles: females; filled symbols: affected individuals; double lines between individuals: consanguineous mating; and a diagonal line through a symbol: a deceased family member. Alleles forming the risk haplotype are shaded black and alleles not co-segregating with retinitis pigmentosa are shown in white.