trisómíu

Trisomy is a type of aneuploidy, which is a condition where an individual has an abnormal number of chromosomes. Specifically, trisomy occurs when a cell has three copies of a particular chromosome instead of the usual two. This can happen with any chromosome, but some trisomies are more common and have recognizable genetic disorders associated with them.

The most well-known example is Trisomy 21, which causes Down syndrome. Individuals with Trisomy 21 have three copies of chromosome 21. Other examples include Trisomy 18, which leads to Edwards syndrome, and Trisomy 13, which results in Patau syndrome. These conditions often involve a range of developmental and physical challenges.

Trisomies typically arise during the formation of egg or sperm cells (meiosis) when chromosomes fail to separate properly, a phenomenon known as nondisjunction. This error can lead to a gamete with an extra chromosome. If this gamete participates in fertilization, the resulting embryo will have trisomy for that specific chromosome. The risk of nondisjunction increases with maternal age.

The effects of trisomy vary depending on which chromosome is involved and the extent of genetic material present in the extra copy. Diagnosis can often be made prenatally through genetic testing such as amniocentesis or chorionic villus sampling, or after birth through karyotyping. While there is no cure for trisomy, medical care and therapies can help manage the associated symptoms and improve quality of life.