Preimplantation genetic diagnosis (PGTA) is an advanced technique used in reproductive medicine to identify potential genetic or chromosomal alterations in embryos before they are implanted in the uterus.
This technique, combined with in vitro fertilization (IVF), has opened a window of possibilities for those couples who are looking to start a family, but who face specific genetic risks. Instead of waiting until pregnancy to find out if a baby may have a genetic disease, PGD allows this evaluation to be carried out at a very early stage, providing peace of mind and better options to couples.
Preimplantation genetic diagnosis not only helps increase the chances of having a healthy pregnancy, but also reduces the risk of transmission of serious inherited diseases. It is a key tool for those with a family history of genetic disorders or for those who have already lived the experience of an affected pregnancy.
What diseases can be detected with preimplantation genetic diagnosis?
PGD allows for the detection of a wide variety of genetic diseases, some of which can have serious or life-threatening effects. These are some of the most common diseases that can be detected using this technique:
1. Monogenic diseases
Monogenic diseases are those caused by mutations in a single gene. Although they may seem uncommon, there are thousands of monogenic disorders that can be passed down from generation to generation. Some of the monogenic diseases that can be detected with PGD are:
- Cystic fibrosis: One of the most common genetic diseases, it affects the lungs and digestive system. Cystic fibrosis causes thick mucus to build up, leading to recurrent lung infections and digestive problems.
- Huntington’s disease: A neurodegenerative disorder that affects motor control and cognitive functions, causing progressive deterioration of the brain.
- Sickle cell anemia: This disorder affects the shape of red blood cells, which can cause blockages in blood vessels, chronic pain, and organ damage.
- Duchenne muscular dystrophy: It is a genetic disease that causes progressive weakness of the muscles, mainly affecting children.
- Thalassemia: An inherited blood disorder that affects the production of hemoglobin, which can lead to severe anemia.
2. Chromosomal alterations
PGTA can also detect abnormalities in the number or structure of chromosomes, which is crucial for preventing pregnancies with severe chromosomal problems. Some of the most common chromosomal abnormalities that can be identified include:
- Down syndrome (trisomy 21): One of the most well-known chromosomal alterations, it occurs when there is an extra copy of chromosome 21. This condition causes delayed intellectual development, distinctive physical characteristics, and possible health problems.
- Turner syndrome: This occurs when a woman has only one copy of the X chromosome instead of two. People with Turner syndrome often have problems with growth, sexual development, and possible heart or kidney difficulties.
- Klinefelter syndrome: This affects men who have an extra copy of the X chromosome (XXY), which can lead to infertility, problems with sexual development, and learning difficulties.
- Trisomy 18 (Edwards Syndrome): A severe chromosomal disorder that affects multiple body systems and can have fatal consequences in the first year of life.
3. X-linked diseases
Some genetic diseases are X-linked, which means that they tend to affect males more severely, as they have only one X chromosome. PGD can detect the following:
- Hemophilia: A disorder that affects the blood’s ability to clot, which can lead to prolonged or dangerous bleeding.
- Fragile X syndrome: A common cause of intellectual disability and developmental problems. Males are more susceptible to this syndrome because of their single copy of the X chromosome.
4. Mitochondrial diseases
PGD can also detect diseases related to mutations in mitochondrial DNA. These diseases are hereditary and affect the functioning of mitochondria, the “energy factories” of cells. Some examples are:
- Leigh syndrome: A serious neurodegenerative disease that affects infants and young children, leading to progressive loss of motor and cognitive functions.
How is PGD performed?
Preimplantation genetic diagnosis is performed on embryos created through IVF before they are implanted in the uterus. The procedure involves:
- In vitro fertilization (IVF): Eggs are obtained from the woman, which are then fertilized with sperm in a laboratory.
- Embryo development: Embryos are cultured in the laboratory until they reach the blastocyst stage (5 or 6 days of development).
- Embryo biopsy: At this point, some cells are removed from the embryo that will form the placenta for genetic analysis. This process is minimally invasive and does not affect the development of the embryo.
- Genetic analysis: The extracted cells are analyzed for genetic mutations or chromosomal abnormalities. These cells are sent out of the country to be processed in reference laboratories such as Igenomix.
- Embryo selection: Only genetically healthy embryos are selected for transfer to the uterus.
Preimplantation genetic diagnosis is a powerful tool for couples facing genetic risks. Not only does this technique help identify serious diseases before embryo implantation, but it also increases the chances of having a healthy pregnancy and a baby free of inherited diseases. At Fertivida, we understand the importance of providing options and peace of mind to people who want to start a family, and we offer all the possibilities to ensure a future without genetic complications.
