LAUSR

PURPOSE To determine whether there is a difference in the prevalence of intraretinal pigment migration (IPM) across age and genetic etiologies of inherited retinal dystrophies (IRDs). DESIGN Retrospective cohort study. METHODS Patients were evaluated at a single tertiary referral center. All patients with a clinical diagnosis of IRD and confirmatory genetic testing were included in this analyses. A total of 392 patients fit inclusion criteria and 151 patients were excluded based on inconclusive genetic testing. Patients were placed into three groups, ciliary and ciliary-related photoreceptor, non-ciliary photoreceptor, and retinal pigment epithelium (RPE), based on the cellular expression of the gene and the primary affected cell type. The presence of IPM was evaluated through slit lamp biomicroscopy, indirect ophthalmoscopy, and wide-field color fundus photography. RESULTS IPM was seen in 257 of 339 patients (75.8%) with mutations in photoreceptor-specific genes and in 18 of 53 patients (34.0%) with mutations in RPE-specific genes (p<0.0001). Pairwise analysis following stratification by age and gene category suggested a significant difference at all age groups between patients with mutations in photoreceptor-specific genes as compared to patients with mutations in RPE-specific genes (p<0.05). A fitted multivariable logistic regression model was produced and demonstrated that the incidence of IPM increases as a function of both age and gene category. CONCLUSIONS IPM is a finding that is more commonly observed in IRDs caused by mutations in photoreceptor-specific genes as compared to RPE-specific genes. The absence of IPM does not always rule out IRD and should raise suspicion for disease mutations in RPE-specific genes.