Most common diseases such as diabetes, cancer or heart disease have a genetic component, which means that part of the risk of developing one of these diseases is inherited from our parents. In recent years, many studies have been developed describing various genetic factors that favor the development of these pathologies. As research progresses, the following question becomes relevant: can we use genetics to predict what pathologies each person will suffer from before they appear?
To answer this question, we must first understand how genetic inheritance works. Genetic information is contained in each of our cells very extensive DNA molecules. Each of us carries two complete copies of all genetic information, inherited from each of our parents. The entire genetic information of an individual is called the genome and contains not only the genes necessary for the production and maintenance of our tissues and organs, but also a large amount of information about how these genes are regulated (when and where they are must). expressed), signals that mark how a non-active region of DNA should fold, and an enormous amount of information whose meaning we have not yet discovered because it is highly repetitive and does not appear to serve any specific function.
In this mess we find all kinds of information and differences between some people and others, which are sometimes important, such as the ability to synthesize a certain protein or not. In other cases we notice subtle changes, e.g. E.g. that the expression of a certain protein is 1% higher in some people or that we have a change in a receptor that makes it slightly less active. These divergences encode what we call our phenotype, the observable differences between people, such as our hair color or our facial features. Certain phenotypic traits are determined entirely by genetics, such as blood type, which follows simple inheritance and is determined by a single gene that SHE. However, there are also others with genetic influence. An example of a genetically influenced trait is height; A person has a genetic predisposition to have a height similar to that of their parents, but environmental factors such as diet and developmental habits also play a key role in a person’s actual height.
In recent years, mathematical models have been developed that make it possible to quantify people’s genetic predisposition to various diseases: polygenic risk indices
The same idea applies similarly when we talk about the inheritance of disease. There are diseases that are entirely genetic, such as phenylketonuria or hemophilia. These pathologies are due to a single variation or change in the genome, which is known in many cases and therefore we can carry out genetic tests and predict them from the moment of birth. However, this is not the case for many of the most common diseases, where both genetic and environmental factors play a role, which is why they are called multifactorial or complex diseases. This means that they do not have a single direct cause in the genome, but rather several changes, called genetic variants, with small effects that together contribute to the development of the pathology. In this case it is not a genetic cause, but a genetic predisposition. In other words, genetics alone do not determine the occurrence of the disease, but rather increase the likelihood of developing it. Still, there is hope because genetic predisposition itself is theoretically predictable.
Mathematical models
It is currently possible to quantify the effect of genetic variants on the risk of disease. This is done through studies in which the complete genome of thousands of people affected by the pathology is compared with the genome of thousands of healthy individuals. This makes it possible to identify those mild effects that promote the development of the disease. Based on these results, mathematical models have been developed in recent years that make it possible to quantify people’s genetic predisposition to various diseases: polygenic risk indices. These models are relatively simple. They consist of a list of identified genetic variants that are associated with a higher or lower risk of a particular disease. To determine a person’s risk score, the number of these variants that a person has in their genome is determined, taking into account how severe the effect of each experimentally observed variant is. Overall, their effects can be added up and an assessment of the individual’s genetic predisposition to the disease can be obtained.
People who have many individual genetic components responsible for a particular disease have a very high predisposition to suffer from it.
Can we then predict whether a person will suffer from a particular disease before it manifests itself? The reality is that we are still a long way from that. These models do not yet have much predictive capacity. Since these diseases also depend on environmental factors, our predictive ability is limited if we only consider genetics, as we only consider one of the components of the pathology. However, these models have great potential to identify individuals with a high predisposition (high risk) to certain diseases. People who have many individual genetic components responsible for a particular disease have a very high predisposition to suffer from it. For different clinical pictures, these models were able to reliably identify groups of people who are more than three times as likely to develop the disease. This has great clinical potential because if these people are identified, personalized plans and recommendations could be made long before symptoms appear, allowing the most serious aspects of the disease to be prevented or detection at early stages when they are still present are a much higher chance that treatments will be effective. In this sense, many clinical trials are being developed to create this type of prevention plans based on identifying high-risk individuals using polygenic risk assessment models.
Individual plans
Finally, it is important to highlight two key aspects. First of all, the genetic predisposition to suffer from a complex disease does not necessarily mean that you have to suffer from it. In contrast to simple genetic diseases, other factors also play a decisive role in the development of complex diseases. Secondly, knowledge of the possibility of suffering from a particular disease makes it possible to create personalized follow-up plans that make it possible to effectively detect the first symptoms of the disease (as in the case of cancer, where early diagnosis is essential). for treatment). Treatment) or prevention plans aimed at maintaining the patient’s quality of life before the symptoms of the most serious stages manifest themselves.
In summary, the ability to predict the occurrence of a disease using genetic data depends on whether the disease is caused or influenced genetically. In the first case, although affordable, the impact on patients’ quality of life may be limited. In the second case, it is not possible to predict the occurrence of the disease, but it is possible to predict the predisposition of a person to suffer from it. This information can be used to create personalized plans, such as lifestyle changes, to act according to a person’s individual risk of suffering from a particular pathology. However, this is still a developing field.
Most common diseases such as diabetes, cancer or heart disease have a genetic component, which means that part of the risk of developing one of these diseases is inherited from our parents. In recent years, many studies have been developed describing various genetic factors that favor the development of these pathologies. As research progresses, the following question becomes relevant: can we use genetics to predict what pathologies each person will suffer from before they appear?
To answer this question, we must first understand how genetic inheritance works. Genetic information is contained in each of our cells very extensive DNA molecules. Each of us carries two complete copies of all genetic information, inherited from each of our parents. The entire genetic information of an individual is called the genome and contains not only the genes necessary for the production and maintenance of our tissues and organs, but also a large amount of information about how these genes are regulated (when and where they are must). expressed), signals that mark how a non-active region of DNA should fold, and an enormous amount of information whose meaning we have not yet discovered because it is highly repetitive and does not appear to serve any specific function.
