Trisomy 18
Chromosomal disorder in which there are three copies of chromosome 18 / From Wikipedia, the free encyclopedia
Dear Wikiwand AI, let's keep it short by simply answering these key questions:
Can you list the top facts and stats about Edward's syndrome?
Summarize this article for a 10 year old
Trisomy 18, also known as Edwards syndrome, is a genetic disorder caused by the presence of a third copy of all or part of chromosome 18.[3] Many parts of the body are affected.[3] Babies are often born small and have heart defects.[3] Other features include a small head, small jaw, clenched fists with overlapping fingers, and severe intellectual disability.
Trisomy 18 | |
---|---|
Other names | Trisomy 18 (T18[1]), chromosome 18 duplication,[2] trisomy E syndrome[3] |
Infant with trisomy 18 | |
Specialty | Medical genetics, pediatrics |
Symptoms | Small head, small jaw, clenched fists with overlapping fingers, profound intellectual disability[3] |
Complications | Heart defects[3] |
Usual onset | Present at birth[3] |
Causes | Third copy of chromosome 18 (usually new mutation)[3] |
Risk factors | Older mother[3] |
Diagnostic method | Ultrasound, amniocentesis[2] |
Treatment | Supportive care[2] |
Prognosis | 5–10% survive past a year old[3] |
Frequency | 1 per 5,000 births[3] |
Most cases of trisomy 18 occur due to problems during the formation of the reproductive cells or during early development.[3] The chance of this condition occurring increases with the mother's age.[3] Rarely, cases may be inherited.[3] Occasionally, not all cells have the extra chromosome, known as mosaic trisomy, and symptoms in these cases may be less severe.[3] An ultrasound during pregnancy can increase suspicion for the condition, which can be confirmed by amniocentesis.[2]
Treatment is supportive.[2] After having one child with the condition, the risk of having a second is typically around one percent.[2] It is the second-most common condition due to a third chromosome at birth, after Down syndrome for a third chromosome 21.[4]
Trisomy 18 occurs in around 1 in 5,000 live births.[3] Many of those affected die before birth.[3] Some studies suggest that more babies that survive to birth are female.[2] Survival beyond a year of life is around 5–10%.[3] It is named after the English geneticist John Hilton Edwards, who first described the syndrome in 1960.[5]