Trisomy 18 or Edwards syndrome

Trisomy 18 or Edwards syndrome


Trisomy 18 or Edwards Syndrome is a genetic disorder caused by the presence of all or part of an extra 18th chromosome. It is named after John H. Edwards, who first described the syndrome in 1960.[1] It is the most common autosomal trisomy, after Down Syndrome, that carries to term.
Trisomy 18 is caused by the presence of three — as opposed to two — copies of chromosome 18 in a fetus or infant's cells. The incidence of the syndrome is estimated as one in 3,000 pregnancies and approximately one in 6,000 live births. The incidence increases as the mother's age increases. The syndrome has a very low rate of survival, resulting from heart abnormalities, kidney malformations, and other internal organ disorders.