Trisomy 18 and 13


The term trisomy describes the presence of three chromosomes instead of the usual pair of chromosomes. For example, trisomy 21, or Down syndrome, occurs when a baby has three #21 chromosomes. Other examples are trisomy 18 and trisomy 13, fatal genetic birth disorders.

  • Trisomy 18 occurs in about one out of every 6,000 to 8,000 live births and trisomy 13 occurs in about one out of every 8,000 to 12,000 live births.
  • It's characterized by severe mental retardation and health problems involving nearly every organ system of the body.
  • Babies with the disorders usually die by age 1, but there have been a few cases in which children survive into their teens.
  • Trisomy 18 is also called "Edwards syndrome" and trisomy 13 is also called "Patau syndrome" after the physicians who first described the disorders.

Trisomy 18 and 13 at Boston Children's Hospital

Decisions surrounding the care of infants with trisomy 18 and 13 are difficult and personal. Your doctors at Boston Children's can connect you with resources available to provide support and help your during this time, including early intervention services, social workers, the hospital chaplain or clergyman and genetic counselors.

Other families who have or have had a baby with trisomy 18 or trisomy 13 are particularly helpful and supportive, since they have experienced many of the same questions and emotions. We can help connect you to families who have faced similar situations.