The vast majority of patients with Stargardt’s disease, as well as half of the recessive cases of cone-rod dystrophy, have mutations in the ABCA4 gene. In addition, this gene is also associated with a considerable number of cases of bull’s eye maculopathy and a small number of families with Retinitis Pigmentosa. All this places ABCA4 as agene with outstanding casuistry in the group of Retinal Dystrophies, and it is for this reason that efforts are being made to design effective therapies.

Most of these treatments depend on the type of mutation and the effect it produces, so the study and prior knowledge of the variants associated with these Retinal Dystrophie is an essential requirement when developing the most appropriate therapies in each case.

The research and identification of variants in the ABCA4 gene is particularly complex, due to its large size (50 exons or DNA coding regions) and its high allelic heterogeneity (more than 1200 mutations described to date). In addition, it may present pathogenic variants in intronic or regulatory regions,in other words, non-coding regions. In fact, it is estimated that between 15-20% of patients are carriers of at least one mutation in these regions, which cannot be analyzed in conventional genetic studies due to their high complexity.