One of the protagonists of Globo’s 9 pm soap opera, Brisa, faces a problem of genetic malformation that prevents her from proving to be the mother of her child: chimerism. But do you know what that is?
Medical geneticist Alexandre Lucidi explains that people with chimerism are born with two distinct genetic materials in their cells. However, the condition can also happen during a stem cell transplant.
“In theory, it happens when there are two embryos fertilized in the uterus that generate two zygotes (same formation of twins). However, the embryos fuse, originating only one baby that has two different genetic materials”, he explains.
In the case of the telenovela, when analyzing Brisa’s DNA, there is no 100% compatibility with her son, who received only part of the character’s material.
What are the symptoms?
Chimerism is a difficult condition to diagnose and symptoms appear infrequently. They manifest with:
- Eyes of different colors;
- Different skin tones;
- Stains of colored or textured hair;
- Disorder of sexual development (genitals with parts of both sexes).
However, there are even other rarer symptoms of having this disorder, such as the death of one of the babies in a twin pregnancy, unexplained failures in parental DNA tests, having two blood types, being left-handed or ambidextrous, and in transgender people .
In the latter case, Lucidi explains that when chimerism involves sex chromosomes (X and Y), brain cells may have these chromosomes different from other cells in the body, theoretically contributing to a transgender identity.
How is the diagnosis made?
The geneticist explains that the STR method, which analyzes the genetic make-up, is the most used, as it evaluates the mix of donor and recipient DNA in the recipient’s blood or bone marrow.
“To perform chimerism analysis, pre-transplant recipient and donor samples are collected and used for comparison with post-transplant recipient samples. Donor and recipient cells are differentiated from one another using unique CNV (copy number variation) markers that provide unique genetic profiles,” says Lucidi.
Although chimerism does not negatively affect a person’s life, the diagnosis can bring benefits to the mental health of those who go through an identity crisis, helping them to understand some phenomena considered inexplicable.
Get news from metropolises on your Telegram and stay on top of everything! Just access the channel: https://t.me/metropolesurgente.