Rare Diseases Genetic Disorders Trisomy 18 and Edwards Syndrome By Mary Kugler, RN Mary Kugler, RN, is a pediatric nurse whose specialty is caring for children with long-term or severe medical problems. Learn about our editorial process Mary Kugler, RN Medically reviewed by Medically reviewed by Keri Peterson, MD on February 07, 2020 facebook twitter linkedin Keri Peterson, MD, is board-certified in internal medicine and operates a private practice, Age Well, in New York City. Learn about our Medical Review Board Keri Peterson, MD Updated on October 25, 2020 Print Human chromosomes come in 23 pairs, each parent supplying one chromosome in each pair. Trisomy 18 (also called Edwards syndrome) is a genetic condition in which one chromosome (chromosome 18) is a triplet instead of a pair. Like Trisomy 21 (Down syndrome), Trisomy 18 affects all systems of the body and causes distinct facial features. Justin Paget / Getty Images Trisomy 18 occurs in 1 in 5,000 live births. Unfortunately, most babies with Trisomy 18 die before birth, so the actual incidence of the disorder may be higher. Trisomy 18 affects individuals of all ethnic backgrounds. Symptoms Trisomy 18 severely affects all organ systems of the body. Symptoms may include: Nervous system and brain: mental retardation and delayed development, high muscle tone, seizures, and physical malformations such as brain defectsHead and face: small head (microcephaly), small eyes, wide-set eyes, small lower jaw, cleft palateHeart: congenital heart defects such as ventricular septal defectBones: severe growth retardation, clenched hands with 2nd and 5th fingers on top of the others, and other defects of the hands and feetMalformations: of the digestive tract, the urinary tract, and genitals Diagnosis The physical appearance of the child at birth will suggest the diagnosis of Trisomy 18. However, most babies are diagnosed before birth by amniocentesis (genetic testing of the amniotic fluid). Ultrasounds of the heart and abdomen can detect abnormalities, as can x-rays of the skeleton. Treatment Medical care for individuals with Trisomy 18 is supportive and focuses on providing nutrition, treating infections, and managing heart problems. During the first months of life, infants with Trisomy 18 require skilled medical care. Due to the complex medical problems, including heart defects, and overwhelming infections, most infants have difficulty surviving to age 1 year. Advances in medical care over time will, in the future, help more infants with Trisomy 18 live into childhood and beyond. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. U.S. Library of Medicine Genetics Home Reference. Trisomy 18. Updated March 2012. Genetic and Rare Diseases Information Center. Trisomy 18. Updated July 7, 2015. Niknejadi M, Ahmadi F, Akhbari F, Afsharian P. Sonographic findings in partial type of trisomy 18. Int J Fertil Steril. 2014;7(4):349–352. Cereda A, Carey JC. The trisomy 18 syndrome. Orphanet J Rare Dis. 2012;7:81. doi:10.1186/1750-1172-7-81