Each gene tells the cell how to make a particular protein, which are the building blocks of our cells and drive many important biological reactions. Slight variations in the genetic instructions create the different characteristics that make us all individuals. Sometimes however, genes contain significant spelling mistakes, or mutations, which mean that the cell cannot read the instructions correctly and the resulting protein will be faulty. Cells containing mutated genes may not function properly. Inherited mutations in genes that are critical for eye health result in abnormal cells in the retina and consequent loss of vision.
Understanding how these faulty genes lead to these retinal abnormalities is a critical step to then being able to investigate potential treatments – it may be possible either to prevent or lessen the harmful effect of these faulty genes on the stability or workings of the retina and its components.
A direct approach to correcting genetic conditions is to replace or edit the faulty gene.
Much effort has been concentrated on finding the faulty genes causing inherited sight loss; this is called ‘gene mapping’. Researchers may then go on to identify the specific fault in the gene that causes the disease.
Research into finding the genes causing inherited retinal diseases has progressed rapidly over the last decade. However, many more genes remain to be identified. In addition to the growing number of known genes (more than 250 genes; July 2018), a large number (sometimes over 100) of different mutations within each of these genes have been found to cause sight loss.
Some of the treatment options being currently studied rely upon knowing which gene is faulty in a particular family or individual, which can be achieved through genetic testing. Participation in some clinical trials is also dependent on knowing the identity of your faulty gene.
Genetic testing is a type of medical test, the results of which can confirm or rule out a suspected genetic condition, or help determine a person’s chance of developing or passing on a genetic disorder.