Trisomy disorders are genetic conditions caused by the presence of an extra chromosome in a person's cells. Normally, humans have 46 chromosomes, arranged in 23 pairs. In trisomy, there are three copies of a specific chromosome instead of the usual two, leading to various developmental and health challenges. The most common trisomy disorder is Down syndrome, which involves an extra copy of chromosome 21. Other types include Edwards syndrome (trisomy 18) and Patau syndrome (trisomy 13). Each of these conditions can result in distinct physical features, cognitive impairments, and increased health risks, affecting individuals differently.