In recent years, genetics has played a key role in identifying molecules that cause the most common diseases, providing a core knowledge base with which to develop treatments in many areas, in particular, ophthalmology. The cells and tissues that make up the eye start growing during embryonic development. A large number of genes are responsible for controlling this process by activating and modulating cell behaviour. It is, therefore, unsurprising that many eye diseases have a genetic origin.
More than 100 genes
The aim of genetic testing is to identify the genetic alteration that causes a disease. Due to their genetic origin, many eye diseases, such as retinitis pigmentosa, Stargardt disease, aniridia, corneal disorders and some forms of glaucoma, are inherited. Over 40 diseases are known to cause retinitis pigmentosa and more than 100 are responsible for retinal dystrophies. Studying all genes and their possible mutations greatly limits manual genetic testing and requires the use of automated and costly strategies. This complexity has led to IMO initiating a research programme, which aims to ensure that the patient receives a complete and personalised diagnosis. Over recent months, IMO’s new basic research department has been carrying out a testing programme for families and isolated cases. Firstly, an ophthalmologist makes a clinical diagnosis, after which the genetics team performs a molecular diagnosis.
The pioneering development of a DNA chip
IMO is committed to basic research to enable patients to benefit from the combining of clinical and genetic knowledge in the study of eye diseases. This combination has been made possible by advances in the knowledge of genetic diseases from a molecular perspective and the development of tools that facilitate the sequencing of genomes and the study of genes in detail. To carry this out, Dr Esther Pomares, from IMO's research team, has developed a highly effective DNA chip for the diagnosis of retinitis pigmentosa. The DNA chip or microarray consists of an arrayed series of microscopic spots of DNA on a solid surface. An automated process rapidly scrutinises the genes that can cause retinitis in at-risk families. This method speeds up the genetic testing process.
Identifying a new gene
One of the results of IMO’s new research programme has been the identification of a gene (PROM1) that causes a severe form of retinitis with macular affectation. This gene had only previously been found in patients with cone dystrophy and macular degeneration. A new gene has, therefore, been added to the family of genes that cause retinitis, and the list of candidates to diagnose has been enlarged to enable prevention and early treatment.