Genetic Therapy of Fuchs Endothelial Corneal Dystrophy: Where Are We? A Review

Objectives: The incidence of Fuchs endothelial corneal dystrophy (FECD) is growing, and with it, the unmet need for a corneal transplant. Among alternative treatment modalities, only genetic therapy represents a causal therapy. Methods: Following the SNARA protocol, the PubMed and ClinicalTrials databases were searched using the keywords Fuchs endothelial corneal dystrophy, FECD, genetic therapy, and CRISPR-Cas9. Results: FECD is polyfactorial disease and mutations or polymorphisms in at least 15 different genes were connected to the disease. For the early-onset form of the disease, exclusive connection to mutations in COL8A2 was confirmed, while for the late-onset form, the most characteristic mutation is the expansion of the CTG18.1 triplet in the TCF4 gene, making these two possible targets. While the CRISPR-Cas9 approach represents the mainstay of genetic therapy development recently, the application of this method to FECD contains several obstacles, studied in preclinical settings. DT-168 and the Ad-Cas9-Col8a2gRNA molecules were developed for FECD treatment and preclinically tested, and phase I and II clinical studies for DT-168 are also already being performed. Conclusions: The review of the literature proved that genetic therapy for FECD is at the level of preclinical research and that there are several specific challenges connected to the target genetic mutation as well as the delivery of possible treatment and duration of the effect. Further studies in the field might bring solutions in the future for alternative treatments for this common corneal disease.