Trisomy 18

Trisomy 18 is a congenital disorder caused by the presence of an extra #18 chromosome, occurring in about 1 out of 3,000 to 1 out of 6,000 live births. Trisomy 18 is always fatal, with 50% of babies dying within the first week and an additional 40% dying within the first year. The disorder is characterized by profound intellectual and developmental disabilities, heart defects, and central nervous system defects. View testing options