Researchers analysed image and genomic data from the UK Biobank to better understand the rare diseases of the human eye. These include the retinal dystrophies – a group of inherited disorders affecting the retina, according to the official statement by the European Molecular Biology Laboratory (EMBL).
This study, published in the journal PLOS Genetics, focused on photoreceptor cells (PRCs), light-detecting cells found in the retina. These can be non-invasively imaged using optical coherence tomography (OCT), which is commonly offered in many opticians today. Using OCT image and genomic data stored in the UK Biobank, researchers generated the largest genome-wide association study of PRCs, according to the statement.
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Rare diseases of the retina are often caused by inherited mutations in genes expressed by PRCs. These can cause the retina to function incorrectly, causing sight impairment or even blindness. Although diseases affecting individuals are rare, together they are the leading cause of blindness in working-age adults.
"We had access to coupled images and genotype data at a scale that had not been seen in a study of this kind," Hannah Currant, a former PhD student at EMBL’s European Bioinformatics Institute (EMBL-EBI) and Postdoctoral Fellow at the Novo Nordisk Foundation Center for Protein Research (CPR) at the University of Copenhagen, said in the statement. "Access to this enormous amount of data was critical to the study and enabled us to identify genetic links to rare retinal dystrophies. This work has identified new avenues for research and generated new questions about rare retinal dystrophies."
Images generated by OCT are high-resolution and can be helpful in identifying the different layers and structures within the retina. These are commonly used to help with the diagnosis of eye disorders. For this study, OCT images and the corresponding genomic and medical information of over 30,000 participants stored in the UK Biobank were used.
The researchers conducted genome-wide association studies (GWAS) using the data to identify genetic variations related to differences in the thickness of the PRC layers. Through this, they could also identify "genomic variations associated with the thickness of one or more of the PRC layers, including those with prior associations with known eye diseases." According to the statement, the newly identified genomic associations are stored and can be openly accessed through the GWAS Catalog.
Several relatively common genetic variants were near genes that are known to cause rare genetic eye diseases when disrupted. The researchers could explore how combinations of these variants change the structure of the retina. This aims for a better understanding of specific rare disease collections to see how these variants might impact disease.
"Systematic bioinformatic analysis of large-scale participant data cohorts is driving the future of genomic medicine," said Omar Mahroo, Professor of Retinal Neuroscience at University College London and Consultant Ophthalmologist at Moorfields Eye Hospital, in the statement. "Having access to these data and being able to make these connections between disease phenotypes and genetic variation will open many new opportunities for modern disease diagnosis and therapeutics."