LAUSR

OBJECTIVE To develop a method to rapidly screen candidate genes for association with recessively inherited progressive retinal atrophy (PRA) in pedigrees of dog in which a causative mutation has not been identified. ANIMAL STUDIED Thirteen PRA-affected dogs were used in this study. PROCEDURES Two microsatellite markers (MS) were designed flanking 45 candidate genes. MS markers were analyzed for heterozygosity and allelic richness. Two dog breeds, in which the causative mutation has been identified (Entlebucher Sennenhunds [ES] and PDE6A-mutant dogs [PDE6A]), were used to validate the MS marker panel. One breed in which the causative mutation is currently unknown (Old English Sheepdog [OES]) was investigated in this study utilizing the MS panel. RESULTS Marker heterozygosity excluded 38 of 45 and 41 of 45 candidate genes (ES and PDE6A, respectively) with each true culprit gene remaining on the list of nonexcluded candidate genes. Additionally, 41 of 45 genes were excluded for OES. CONCLUSIONS This tool set was used quickly and efficiently to narrow down 45 candidate genes for recessively inherited PRA in two types of dogs with known mutations and one type of dog with an unknown mutation.