**1. Introduction**

Inherited forms of retinal degeneration (RD) encompass a genetically and clinically heterogeneous group of disorders estimated to cause vision impairment and loss in more than 5.5 million individuals worldwide [1,2], with 282 mapped and identified retinal degenerative disease genes documented in the RetNet human database [3]. Animal models, such as non-human primates [4], dogs [5], mice [6,7], zebrafish [8], and fruit flies [9], have been used to identify candidates for human retinal disease genes, to elucidate pathological mechanisms, and to serve as a resource for exploring therapeutic approaches. As potential therapies for retinal diseases are investigated, the need for animal models increases. Information about the disease onset and rate of progression, the pathogenic pathways involved, and the genetic background in which the disrupted genes are situated are all factors that

must be considered when selecting appropriate models for testing therapeutics. These factors will also play a role in interpreting the outcome of treatment studies.

The purpose of this review is to compile a searchable list of mouse models of inherited retinal diseases caused by single gene mutations that specifically lead to the post-developmental rod and/or cone photoreceptor (PR) cell loss. To identify these models, we reviewed mouse-specific data available in the Mouse Genome Informatics (MGI) and National Center for Biotechnology Information (NCBI) databases at The Jackson Laboratory (JAX) and National Institutes of Health (NIH), respectively. We recorded, when available, PR cell loss data from publications describing mutant alleles of the genes identified. We also included representative fundus photographs and optical coherence tomography (OCT) images of selected mouse models from the Eye Mutant Resource (EMR) and the Translational Vision Research Models (TVRM) programs at JAX as examples of the retinal phenotypes found among mouse models that fit our criteria. We attempted to cluster genes based on the function and then compared the progression of PR cell loss among these clusters to provide potential insights into disease mechanisms. We also compared our list of mouse genes associated with PR cell loss with the RetNet gene list, to highlight mouse models for specific retinal diseases, to reveal opportunities to create novel models, and to identify candidate genes within human loci for which a causative gene is currently unknown. Finally, we coordinated with the MGI team to incorporate our annotations into the MGI database, which will allow future analyses using tools available through that platform. It is hoped that our work will be useful as a resource for investigators to assist in the selection of appropriate mouse models within and across functional clusters in new studies to understand and develop treatments for human retinal degenerative disease.

In the three decades since the genes linked to PR loss phenotype were first identified in the mouse and human [10–12], rapid progress in understanding the genetic basis of inherited RD has been summarized in many excellent reviews. Many of the topics presented in the current article have been discussed previously in reviews of mouse RD models [6,7,13,14] and in summaries of our work at JAX [15–21]. Although we have made every e ffort to acknowledge the many contributions to this field, we note that there is a large body of relevant literature and apologize in advance to authors whose reviews or articles we may have inadvertently overlooked.
