Edwards syndrome

Trisomy 18, also known as Edwards syndrome is a trisomy. It is a genetic disorder. People with trisomy 18 have three copies of chromosome 18. "Normal" people have two copies of the chromosome. It is named after John H. Edwards, who first described the syndrome in 1960. It is the second most common autosomal trisomy, after Down Syndrome, that carries to term. 
It is estimated that about one in 3,000 live births are affected. The incidence increases as the mother's age increases. The syndrome has a very low rate of survival. People with Edwards syndrome often have heart abnormalities, kidney malformations, and other internal organ disorders. 
About 95% of the babies with Edwards syndrome die before they are born. About half of all babies born with the condition will reach two months of age, and only 5-10% will survive for a year. The median life span is five to fifteen days. One percent of children born with this syndrome live to age ten, typically in cases of the less severe mosaic Edwards syndrome.