Trisomy 18: Symptoms & Signs

Medically Reviewed on 9/24/2020

Trisomy 18 is a genetic condition also known as Edwards syndrome. Like Down syndrome, trisomy 18 is associated with advanced maternal age.

Many fetuses with trisomy 18 do not survive to birth. Affected infants who do survive have a number of congenital abnormalities, which can include an

  • abnormally small head,
  • absence of one or both testes,
  • neurodevelopmental delays,
  • failure to thrive,
  • low birth weight,
  • short stature,
  • underdeveloped jaw,
  • drooping of upper eyelid or wide-spaced eyes,
  • abnormal deviation of fingers, and
  • clenched hands.

Abnormalities of multiple organs may be present. The average life span for infants born with trisomy 18 is 3 days to 2 weeks.

Cause of trisomy 18

The presence of an extra copy of chromosome 18 causes the genetic condition.

Other trisomy 18 symptoms and signs

  • Abnormal Deviation of Fingers
  • Abnormally Small Head
  • Absence of One or Both Testes
  • Clenched Hands
  • Drooping of Upper Eyelid or Wide-Spaced Eyes
  • Failure to Thrive
  • Low Birth Weight
  • Neurodevelopmental Delays
  • Short Stature
  • Underdeveloped Jaw

Jameson, J. Larry, et al. Harrison's Principles of Internal Medicine, 20th Ed. New York: McGraw-Hill Education, 2018.