Trisomy 18, also known as Edwards Syndrome, is caused by an error in cell division known as meiotic disjunction. Instead of the normal pair, an extra chromosome 18 (triple) results and disrupts the normal pattern of development in significant ways that can be life-threatening, even before birth. The developmental issues that can be caused by Trisomy 18 are associated with more medical complications that are more potentially life-threatening in the early months and years of life. However, the level of severity differs case by case, and some children enjoy many years of life with their families.
For more information, visit the Trisomy 18 Foundation