Trisomy 18

Symptoms

What are the main signs and symptoms of trisomy 18?

Babies with trisomy 18 are often born very small and frail. They have serious medical problems and physical defects including: overlapping fingers, clenched fists and a specific type of foot defect called 'rocker bottom feet'. They may also have heart defects, low set ears, intellectual issues and brain problems. They usually have growth difficulties, which can be seen by ultrasound before the baby is born. Babies with trisomy 18 often have respiratory and feeding difficulties. Most pass away in utero or shortly after birth but those that survive after birth generally have severe intellectual disability.

References
  • http://ghr.nlm.nih.gov/condition/trisomy-18
  • http://rarediseases.org/rare-diseases/trisomy-18-syndrome/
  • Am J Med Genet A. 2016 Apr;170(4):825-37. doi: 10.1002/ajmg.a.37495. Epub 2015 Dec 10.Survival of children with trisomy 13 and trisomy 18: A multi-state population-based study.Meyer RE1, Liu G2, Gilboa SM3, Ethen MK4, Aylsworth AS5, Powell CM5, Flood TJ6, Mai CT3, Wang Y7, Canfield MA4; National Birth Defects Prevention Network.
Show More Content Like This

More Symptoms Content

Are there earlier onset or later onsets of Trisomy 18?

Is there variable expression in the Trisomy 18?

What is the difference between Trisomy 18 and mosaic Trisomy 18?

Will my child be less severely affected if they have mosaic Trisomy 18?

How long can a baby live with Trisomy 18?

Are babies with Trisomy 18 always born prematurely?

Are there earlier onset or later onsets of Trisomy 18?

There are not different onsets for trisomy 18. The extra copy of chromosome 18 is present in the baby's cells from early in prenatal development, most often conception. Some symptoms of trisomy 18 are revealed through prenatal ultrasounds or prenatal testing. Babies with complete trisomy 18 will almost always have symptoms before birth, such as growth being slower than expected while in the womb. Therefore, all babies with trisomy 18 are diagnosed either prior to birth or very early in life.

References
  • http://rarediseases.org/rare-diseases/trisomy-18-syndrome/
  • Obstet Gynecol Surv. 2016 May;71(5):295-300. doi: 10.1097/OGX.0000000000000304.Management Considerations for Ongoing Pregnancies Complicated by Trisomy 13 and 18.Dotters-Katz SK1, Kuller JA2, Grace MR1, Laifer SA3, Strauss RA4
Is there variable expression in the Trisomy 18?

There can be variable expression among children with trisomy 18. A baby with trisomy 18 will likely not have every possible symptom. Certain symptoms, like intellectual disability, are predicted to be found in most babies with trisomy 18. Degree of symptom severity may depend on how many cells in the body have three copies of chromosome 18. The term mosaicism is used if not all cells in the body have three copies of chromosome 18. Typically, only blood cells are tested to diagnosis trisomy 18. Some medical professionals believe that individuals with less severe trisomy 18 may have some cells with only 2 copies of chromosome 18 but this is hard to prove since samples of tissue from other parts of the body are not easily available to test. A sample of skin may be tested if mosaic trisomy 18 is suspected.

References
  • http://rarediseases.org/rare-diseases/trisomy-18-syndrome/
What is the difference between Trisomy 18 and mosaic Trisomy 18?

When someone has three copies of chromosome 18 in all of their cells, they have complete trisomy 18. Around 95% of children with trisomy 18 have complete trisomy 18. The other 5% have mosaic trisomy 18. This means that some of their cells have 2 copies of chromosome 18, and other cells have 3 copies of trisomy 18. Almost all mosaic trisomy 18 babies begin with full trisomy 18 and then a cell and all the cells from that cell, lose one of the #18 chromosomes. This is how mosaicism occurs.

References
  • http://rarediseases.org/rare-diseases/trisomy-18-syndrome/
  • http://ghr.nlm.nih.gov/condition/trisomy-18
  • BMJ Case Rep. 2015 Nov 11;2015. pii: bcr2015211587. doi: 10.1136/bcr-2015-211587.Phenotypic extremes in liveborn monozygotic twins with mosaic Edwards syndrome.Bussmann N1, Cunningham K1, Green A2, Ryan CA3
Will my child be less severely affected if they have mosaic Trisomy 18?

How severely affected an individual is from mosaic trisomy 18 depends on which cells in the body have the 2 copies of chromosome 18 and which have 3. If all of the heart cells have 3 copies of chromosome 18, the risks to have a heart defect may be the same. If all of the kidney cells have 2 copies of chromosome 18, the risks to have a kidney abnormality may be lower. Mosaicism is very complicated, and it is challenging to predict how a baby will be affected. Typically, children with mosaic karyotypes are less severely affected however, than children with full trisomy 18.

References
  • http://rarediseases.org/rare-diseases/trisomy-18-syndrome/
  • Am J Med Genet A. 2016 Apr;170(4):825-37. doi: 10.1002/ajmg.a.37495. Epub 2015 Dec 10.Survival of children with trisomy 13 and trisomy 18: A multi-state population-based study.Meyer RE1, Liu G2, Gilboa SM3, Ethen MK4, Aylsworth AS5, Powell CM5, Flood TJ6, Mai CT3, Wang Y7, Canfield MA4; National Birth Defects Prevention Network.
  • BMJ Case Rep. 2015 Nov 11;2015. pii: bcr2015211587. doi: 10.1136/bcr-2015-211587.Phenotypic extremes in liveborn monozygotic twins with mosaic Edwards syndrome.Bussmann N1, Cunningham K1, Green A2, Ryan CA3
How long can a baby live with Trisomy 18?

The life expectancy of an individual with trisomy 18 can vary considerably. The heart defects and breathing difficulties, and other organ abnormalities associated with trisomy 18 can make it difficult for babies to survive. Some babies with trisomy 18 will die before birth, and be born stillborn. Other times, babies live to delivery but they may pass away a few hours or days later. Around 5% to 10% of babies with trisomy 18 are able to survive through the first year. Currently, the longest anyone has lived with trisomy 18 is into their 20s.

References
  • http://rarediseases.org/rare-diseases/trisomy-18-syndrome/
  • http://ghr.nlm.nih.gov/condition/trisomy-18
  • Am J Med Genet A. 2016 Apr;170(4):825-37. doi: 10.1002/ajmg.a.37495. Epub 2015 Dec 10.Survival of children with trisomy 13 and trisomy 18: A multi-state population-based study.Meyer RE1, Liu G2, Gilboa SM3, Ethen MK4, Aylsworth AS5, Powell CM5, Flood TJ6, Mai CT3, Wang Y7, Canfield MA4; National Birth Defects Prevention Network.
Are babies with Trisomy 18 always born prematurely?

Not all babies with trisomy 18 are born prematurely. A baby born between 37 and 42 weeks of gestation is considered full term. Around 1/3 of babies with trisomy 18 are born before 37 weeks of gestation.

References
  • http://rarediseases.org/rare-diseases/trisomy-18-syndrome/
  • Pediatr Neonatol. 2009 Aug;50(4):147-51. doi: 10.1016/S1875-9572(09)60053-X.Changing clinical presentations and survival pattern in trisomy 18.Hsiao CC1, Tsao LY, Chen HN, Chiu HY, Chang WC

We use cookies to ensure that we give you the best experience on our website. By continuing to browse this site, you are agreeing to our use of cookies.

Continue Find out more about our use of cookies and similar technology

This content comes from a hidden element on this page.

The inline option preserves bound JavaScript events and changes, and it puts the content back where it came from when it is closed.

Remember Me