Molecular Genetics in Ophthalmology
The field of genetics is currently experiencing enormous advances in the diagnosis and treatment of some eye diseases.
What is Molecular Genetics?
Many eye diseases have a genetic component and can therefore be inherited and transmitted through many generations of a family.
Genetic studies allow us to know whether a patient carries mutations. A mutation is a change in the normal structure of our genes that can be inherited or re-emerge in an individual.
How is it useful?
A family study allows us to detect unknown cases of the disease or cases that have not caused symptoms. We can therefore start treatment early in order to slow down disease progression or even prevent its onset. We can also give a more accurate visual prognosis on comparing your type of mutation with other previously known mutations. Treatment can therefore be more effective and personalised.
Furthermore, we can give genetic counselling when informing couples about the chances of conceiving a baby with the disease.
Which diseases and genes are studied in Molecular Genetics?
There are various hereditary eye diseases that are likely to be studied genetically, such as glaucoma and retinal degenerations such as retinitis pigmentosa.
In the case of glaucoma, we study the myocilin (MYOC) and CYP1B1 genes. The MYOC gene has been associated with a small percentage of cases of chronic open-angle glaucoma in adults but its involvement is greater in juvenile-onset open-angle glaucoma. Certain mutations described in this gene lead to particularly severe glaucoma and genetics allows us to plan a more intensive treatment from the very start. The CYP1B1 gene has been associated with primary congenital glaucoma and studying this gene is of special interest when providing genetic counselling to families who have already experienced this severe pathology.
We also offer a genetic study of certain symptoms associated with glaucoma, such as Rieger syndrome, since symptoms are not exclusively ocular but can affect other organs of the body. In this case we study the FOX and PITX genes.
In the case of hereditary chorioretinal dystrophies, the rhodopsin and peripherin genes are primarily studied.
Is it available at ICO?
ICO is a pioneer in the study of the genetic code of families with eye diseases. We have vast experience in the field of glaucoma, having studied more than 300 families from all over Spain. ICO's experience in the field of genetics is supported by numerous conferences and scientific publications.
How is it done?
Genetic screening is a simple procedure that only requires a single non-fasting blood test. Possible mutations or genetic variations in the patient and his/her relatives are investigated at a sophisticated laboratory.
What are the technological principles?
DNA containing all the required genetic information is extracted from the small blood sample taken. This fraction of microscopic substance can be greatly amplified thanks to the technique called polymerase chain reaction (PCR). All the nucleotides present in the DNA sequence are then checked one by one against a normal DNA model to see if there is a genetic variation at any position. This is what we call a mutation and it is the fault that is ultimately causing the pathology in question.
Finally, the ophthalmologist specialising in ocular genetics relays all this information to the patient so that they can decide on any resulting practical applications together.