trisomy 18
Last reviewed 01/2018
Edward's syndrome is a rarer cause of mental retardation than Down's syndrome, and a more severe disease. About 30% of babies with this condition die in the first month and fewer than 10% survive the first year.
The incidence of this condition is about 1 per 6000 live births, with a male to female ratio of 1:2. There is a weak association with advanced maternal age.