Trisomy 18

Edwards Syndrome

What is Trisomy 18?

  • Trisomy 18 occurs when a baby has 3 #18 chromosomes instead of the normal 2.

  • Occurs in approximately 1 out of every 2500 pregnancies in the United States and about 1 in every 6000 live births.

  • There are 3 types of Trisomy 18

  1. Full Trisomy 18 - The extra chromosome occurs in every cell of the body. This is the most common type of Trisomy 18 occurring in about 95% of all cases. This type is not hereditary.
  2. Partial Trisomy 18 - Only part of the extra chromosome is present. This type is very rare and may be caused by hereditary factors.
  3. Mosaic Trisomy 18 - The extra chromosome is present in some but not all of the cells of the body. This type is very rare and is not inherited.

  • Trisomy 18 can be diagnosed before birth by performing and amniocentesis and through ultrasounds. If not diagnosed before birth the baby will have blood screenings done to get a definite diagnosis.


  • Unlike Down Syndrome the developmental issues are associated with medical complications that are much more life threatening in the early months and years of life.
  • 50% of babies carried to term will be stillborn. Boys have a higher stillbirth rate than girls
  • Less than 10% of babies will survive to see their first birthday.

Characteristics/Birth Defects and Disorders associated with Trisomy 18

  • Heart Defects
  1. Ventricular Septal Defect (VSD) - a hole between the lower chambers of the heart
  2. Atrial Septal Defect (ASD) - a hole between the upper chambers of the heart
  3. Coarctation of the aorta: a narrowing of the exit vessel from the heart.
  • Kidney problems
  • Clenched hands
  • Pocket of fluid on the brain
  • Rocker bottom feet
  • Delayed growth
  • Small jaw and small head
  • Low set ears
  • Sever developmental delays
  • Umbilical hernia
  • Cleft lip


  • Feeding difficulties
  • Gastroesophegeal reflux
  • Slow post natal grow
  • Apnea
  • Seizures
  • Kidney defects
  • Urinary tract infections
  • Scoliosis

Impact On The Family

Emotionally Devastating

  1. Denial and Isolation
  2. Anger
  3. Bargaining
  4. Depression
  5. Acceptance


  • Individuals with Trisomy 18 will require medicine and different types of therapy.
  • Doctors visits and hospital stays are not cheap.
  • Funeral arrangements


Unfortunately most individuals do not live to see the inside of a classroom, however a few do and these students will need a lot of support to continue to grow and learn.

  • Therapy should be provided (OT, PT, Speech)
  • Different forms of assistive technology should be available (standers, wheelchairs, communication devices, etc.)
  • Teachers and paras should be trained on how to meet the needs of the student (tracheostomy care, tube feeding, etc.)

Meet Mieko

Mieko's 1st Year-Trisomy 18 News Story
Mieko attended preschool where she received therapy and eventually learned how to walk with the assistance of a walker and crutches. She was a very happy little girl who loved to laugh and smile. However her life was sadly cut short at the age of 4 due to complications form Trisomy 18.

Meet Carly

Carly's fifth birthday