4D Molecular Therapeutics announced the enrollment of the first participant in its Choroideremia Natural History Study (NHS). This study is an important step in developing a gene therapy product optimized for intravitreal administration to treat Choroideremia (CHM) patients. 4DMT has deployed its proprietary AAV vector discovery platform, Therapeutic Vector Evolution, to create and optimize a proprietary AAV vector for intravitreal delivery to the retina. This vector is designated to be the basis for the first 4DMT experimental gene therapeutic targeted for the treatment of CHM. 4DMT is working in close collaboration with the Choroideremia Research Foundation on CHM product development and the Natural History Study. The NHS is a multi-center US-based study designed to evaluate disease progression in a wide variety of individuals with CHM. Understanding more about clinical endpoints as the disease progresses will aid in identifying both potential participants and the best clinical measures for upcoming 4DMT clinical trials. Participants in the study will be assessed periodically over two years. At each visit, they will undergo a series of photographic, imaging and clinical evaluations. Two clinical sites are actively recruiting for the study: Retina Foundation of the Southwest, Dallas, Texas (Principal Investigator Dr. David Birch). Retina Vitreous Associates of Los Angeles (Principal Investigator Dr. David Liao). Choroideremia is an X-linked retinal disease that begins as night blindness in childhood and progresses to complete blindness. It affects 1 in 50,000 people in the United States, predominantly males, and has no effective treatment.