Figure 3. Pedigree of an extended family of MLHDs with shared environment. The family tree of Family K shows the proband (arrow), the dog’s three siblings from another pregnancy, and 14 other related members for which the retinal phenotype was examined over a period of 1.4 to 4.2 years. In the PRA affected cases, the age (y, years) under each symbol indicates the age of onset of behavioral (bold symbols) or fundoscopic (hatched symbols) abnormalities. In the dogs with no apparent visual dysfunction, the age corresponds to that at the last fundoscopic examination. Some members of the family were not examined in this study and are omitted from the pedigree. The following symbols are used: square, male; circle, female; bold, blind; hatched, abnormal fundus with no apparent visual dysfunction; white, no fundoscopic abnormality with no apparent visual dysfunction. RPGRIP1 genotypes are denoted as follows: wildtype homozygote, in blue (+/+); heterozygote, in yellow (+/−); insertion homozygote, in red (−/−).