The genetic studies conducted by IMO analyse the probability of transmitting glaucoma hereditarily and facilitate early detection in asymptomatic family members
To mark World Glaucoma Week, which runs until next Saturday, IMO Foundation has launched an awareness-raising and prevention campaign. Under the title “Breaking the siege on vision. Fighting back against glaucoma.
Activities Glaucoma Awareness Week in IMO
The campaign recommends, as the main preventative measure, biannual eye check-ups for people over the age of 40 and annual check-ups for anyone within the main risk groups. Among them are people with ocular hypertension, high myopia and other serious vision problems, black or Asian people and, especially, the over 65s and those with a family history of glaucoma, given the significant genetic component of the disorder.
IMO carries out genetic testing in cases of hereditary glaucoma to identify the molecular cause of the disorder and complement its clinical diagnosis. Knowledge of the molecular abnormality enables IMO to provide genetic counselling to families, identifying the disorder’s pattern of inheritance and revealing the likelihood of transmitting it. It also alerts family members who are carriers to the fact that they have not yet developed the disorder but are likely to suffer from it in the future, and provides a prognosis of the disorder (how it will evolve), which directly affects the patient’s prospects and, especially, the treatment of the disorder.
According to Dr Esther Pomares, head of IMO’s Genetics Department, “studying the disorder’s genetic basis results in greater and better understanding and facilitates the identification of new genes responsible for glaucoma and new risk factors not associated with the disorder until now. Genetic counselling for families also enables early diagnosis of asymptomatic family members and lays the foundations for effective future gene therapy.”
In the molecular biology laboratory of IMO’s Genetics Department, genomic DNA extraction is carried out from blood samples provided by the patient and his or her family members. Once the DNA is purified, direct sequencing of the relevant genes is performed (those that are described as being responsible for hereditary glaucoma) to identify the mutation or pathogenic abnormality. With this information, it is possible to identify asymptomatic carriers early and establish the transmission pattern of the disorder and its prognosis.
Genetic risk factors
Glaucoma is a disorder with certain heterogeneous genetic bases, given the existence of some Mendelian inheritance cases (direct transmission from generation to generation) and other sporadic cases of complex inheritance, in which the percentage of affected members of the same family is higher than the population average.
In these cases, however, only genetic risk factors, and not the specific genetic cause, are known, making it difficult to establish a clear cause-effect relationship between the molecular basis and the development of the disorder.
Currently, there are known polymorphisms (genetic risk alleles) in 25 genes associated with the disorder, while mutations have been described in about ten glaucoma genes with Mendelian inheritance. Given current diagnostic possibilities, IMO is committed to studying cases of Mendelian inheritance in families because, despite affecting a smaller number of patients, they have much clearer molecular bases and, therefore, enable an accurate genetic diagnosis to be provided.
Dr Esther Pomares explained the cases of hereditary glaucoma to a group of opticians and pharmacists who attended an information session hosted by IMO on 7 March to mark World Glaucoma Week. The talk, entitled “Objective: diagnose the 50% of patients who have glaucoma but do not know it”, also involved the participation of IMO glaucoma specialists, Dr Sílvia Freixes and Dr Elena Arrondo, who explained the key aspects of the disorder.