triszómiák

Trisomy is a genetic condition characterized by the presence of an extra chromosome in a cell. This extra chromosome can occur in any of the 23 pairs of chromosomes that humans typically have. The most common trisomies are trisomy 21, trisomy 18, and trisomy 13, which are associated with Down syndrome, Edwards syndrome, and Patau syndrome, respectively. These conditions are typically detected during prenatal screening or after birth through karyotyping, a technique that analyzes the chromosomes in a person's cells.

Trisomy 21, the most common form of trisomy, is caused by the presence of an extra copy of chromosome 21. Individuals with trisomy 21 often have characteristic physical features, including a flat facial profile, epicanthal folds (epicanthus), a small stature, and a single crease in the palm of the hand (simian crease). They may also experience intellectual disabilities and other health issues, such as heart defects and increased risk of leukemia.

Trisomy 18, also known as Edwards syndrome, is caused by the presence of an extra copy of chromosome 18. Individuals with this condition typically have severe intellectual disabilities and multiple physical abnormalities, including rocker-bottom feet, clenched fists, and overlapping fingers. They also have a high risk of heart defects and other congenital anomalies.

Trisomy 13, or Patau syndrome, is caused by the presence of an extra copy of chromosome 13. This condition is often fatal in the first year of life due to severe physical abnormalities and intellectual disabilities. Individuals with trisomy 13 may have a small head, microcephaly, and other distinctive physical features.

Trisomies can occur spontaneously or may be inherited from a parent who carries an extra chromosome. Prenatal testing and genetic counseling can help individuals and families understand the risks and make informed decisions. While trisomies are generally considered genetic disorders, ongoing research aims to improve our understanding of their causes and potential treatments.