Being a carrier of a genetic disease means that we have a variant in our genetic material linked to that disease. This variant doesn't cause the disease and usually doesn't cause any symptoms, so why is it important to know if we are carriers? In this article, we explain what it means to be a carrier and why it's important.
A brief introduction to genetics
DNA is a complex molecule found in virtually every cell of our body and contains the instructions necessary for the creation, development, and reproduction of life. Within DNA, we can distinguish specific fragments called genes, which contain the information needed to produce proteins that carry out multiple functions in the body.
The complete set of our DNA is called our genome. DNA is compacted within cells, reaching its maximum degree of compaction during cell division, when chromosomes appear. Humans generally have 46 chromosomes in total, 23 inherited from our father and 23 from our mother. This means that, having two copies of each chromosome, we have two copies of all our genetic information and, therefore, two copies of each gene.
As you may have noticed, children resemble their parents, and this is because, as we have said, DNA is inherited from parents to children, which is known as genetic inheritance. We can imagine the genome as the instruction manual we inherit from our parents, determining everything from our eye and hair color and height to traits that, in addition to having a genetic component, also depend on other factors such as lifestyle and environment. But it's not just our traits that are inherited; diseases can also be inherited, and sometimes many members of a family may share the same illness.
Monogenic and inherited diseases
As we have already mentioned, DNA is our instruction manual and, therefore, an error, commonly known as a “mutation”, can alter some of the instructions in this manual and ultimately cause a disease.
In terms of inheritance, the genetic diseases with the greatest impact are monogenic diseases. In these pathologies, an alteration in a specific gene can lead to the disease. A key factor in this type of disease is the mode of inheritance. We can distinguish two main modes of inheritance in monogenic diseases:
- Dominant inheritance: in these cases only one altered copy of the gene is enough to cause the disease.
- Recessive inheritance: both copies of a gene must be altered for the disease to appear. If we only have one copy of the altered gene, we will not develop the disease, but we will be carriers.
The importance of knowing our carrier status
As we've mentioned, being a carrier of a recessive genetic disease generally means you won't experience any symptoms. Even so, it's important to know if you're a carrier when considering starting a family. Why? Because if your partner is also a carrier of the same disease, there's a high probability that their children will inherit both altered copies of the gene and, in that case, will have the disease. This is why knowing your carrier status is so important.
Zogen DNA tests, such as the test Health Check, They are a useful tool for knowing the carrier's condition.
There are some terms worth clarifying when discussing "carriers." When we want to refer to whether a person is a carrier of a disease, we generally speak of "carrier status." Another term you might hear is "carrier rate" or "carrier frequency." These terms refer to how common it is to be a carrier of a particular disease. The carrier rate varies depending on the disease. If a disease has a carrier rate of 1 in 25, it means that even if they are unaware of it, 1 in 25 people will be a carrier of the disease.
Most common recessive genetic diseases
Although it depends on the geographic area and population, some recessive diseases have a higher carrier rate. This increases the likelihood that both partners will be carriers of the same disease and, therefore, of having a child who develops it.
Some of the diseases that have a high carrier rate are:
- Cystic fibrosisThis is a disease that affects approximately 1 in 4,500 people, and its carrier rate is estimated at 1 in 25. It is a multisystemic disease that affects various parts of the body, primarily the respiratory and digestive systems.
- Phenylketonuria (PKU) is a disease that affects 1 in 10,000 newborns in Europe. People with PKU are unable to break down a molecule called phenylalanine, which accumulates in the body, causing various symptoms such as neurological problems and developmental delays. In some countries, such as Ireland and Turkey, the prevalence of PKU is approximately 1 in 30 people.
- Hemochromatosis: It is estimated to affect 2-5 people per 1,000 Caucasians. It is an iron metabolism disorder that causes excessive iron buildup in the body. The carrier rate is estimated to be 1 in 10-12 people.
- Spinal muscular atrophyOne in 40-50 people carries this disease. It belongs to a heterogeneous group of pathologies called muscular dystrophies, in which there is a progressive destruction of lower motor neurons, and it is estimated to affect one in 6,000 newborns worldwide.
Today, we have genetic testing that allows us to determine if we are carriers of recessive diseases. When both partners are carriers of the same disease, the risk of their offspring developing the disease is 25% with each pregnancy. In other words, being a carrier does not mean that the person has the disease, but it does mean they have a risk of passing it on to their offspring.
At Zogen, we are committed to proactive healthcare at every stage of life. We offer a wide range of genetic tests and have a team of medical geneticists to guide you toward the most appropriate test for your individual needs. For more information, please don't hesitate to contact us.
Find your ideal test here: https://zogen.local/tu-test-ideal/
