Identification of new retinal dystrophies genes and characterization of genotype-phenotype correlations

Identification of new retinal dystrophies genes

The aim of this research project is to identify new causative genes of retinal dystrophies, in order to contribute to the knowledge and diagnosis of these diseases.

Research team

Principal: Dr Esther Pomares

Co-researchers: Dr Víctor Abad (Genetics Department) and Dr Anniken Burés, Dr Borja Corcóstegui and Dr Rafael Navarro (Retina and Vitreous Department)

Funding

Donations from individuals

Duration

September 2014 - present

Project description

Retinal dystrophies (RD) are a heterogeneous group of hereditary diseases characterized by the degeneration of photoreceptors and the retinal pigment epithelium. They are one of the main causes of blindness in adults and affect approximately 1 in 3,000 people. These diseases present a high degree of clinical overlap, with very subtle differences between some pathologies; a high genetic heterogeneity, with more than 300 causal genes; and a great phenotypic heterogeneity, since many of these genes are associated with more than one retinal dystrophy.

Despite the high number of genes that can cause RD, they do not explain all cases and, in fact, it is estimated that 20% of the families are carrying mutations in genes that have not yet been identified. This great heterogeneity makes the genetic analysis of RDs extremely complicated, since it is impossible to address them using conventional methodological strategies. For all these reasons, the main objective of this project is the identification of new genes and new mutations responsible for the different types of retinal dystrophies, through the use of recent next generation sequencing technologies, in order to establish new genotype-phenotype correlations and contribute to the knowledge and diagnosis of these diseases.

Current status of the project

January 2021

In the first phase of the project, a genetic analysis tool was designed and developed with high efficiency to identify the molecular causes in different cases of families affected by retinal dystrophies. This new diagnostic methodology, as well as the results obtained, were published in a high impact international scientific journal. Likewise, in later stages, new genotype-phenotype correlations were established for two genes responsible for retinal dystrophies: RP1 and DRAM2.

In both cases, functional and expression studies were performed in order to characterize the identified pathogenic variants, which were also published in international scientific journals of high impact in the field of ophthalmology.

Recently, the IMO Foundation research team has identified a new mutation not described to date in the ARSG gene, which was first linked in 2018 to Usher Syndrome, a retinal dystrophy that causes visual and hearing loss. These findings have led to confirmation of the existence of a 4th type of the disease, and have been published in the prestigious scientific journal American Journal of Ophthalmology Case Reports.

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