CampusDownWiki CampusDown ↗
English

Down Syndrome

🩺 Nursing & Health By CampusDown Wiki Editorial Team Last updated
Quick answer: Down syndrome is a chromosomal condition caused by an extra copy of chromosome 21, associated with intellectual disability, characteristic features and certain health conditions.
Contents
  1. 1. Cause and types
  2. 2. Features and associated conditions
  3. 3. Diagnosis and support
  4. 4. References

Cause and types

John Langdon Down described the condition in 1866, and Lejeune and colleagues identified the extra chromosome 21 in 1959. About 95% of cases are standard trisomy from nondisjunction during meiosis; others are translocation or mosaic forms. Risk rises with maternal age.

Features and associated conditions

  • Mild to moderate intellectual disability, speech delay and low muscle tone are common.
  • Typical features include a flat facial profile, upward-slanting eyes and a single palmar crease.
  • Congenital heart defects (about 40-50%), hypothyroidism, hearing and vision problems and early-onset Alzheimer's disease are more frequent.

Diagnosis and support

Prenatal screening uses blood tests, nuchal translucency ultrasound and cell-free DNA testing, with diagnosis confirmed by chorionic villus sampling or amniocentesis. Early intervention, inclusive education and regular health checks greatly improve outcomes; life expectancy now reaches around 60.

References

  1. Bull, M. J. (2020). Down syndrome. New England Journal of Medicine, 382(24), 2344-2352.
  2. Antonarakis, S. E., et al. (2020). Down syndrome. Nature Reviews Disease Primers, 6, 9.
  3. Lejeune, J., Gautier, M., & Turpin, R. (1959). Étude des chromosomes somatiques de neuf enfants mongoliens. Comptes Rendus de l'Académie des Sciences, 248, 1721-1722.

Reports and materials that use this theory (Korean)

There are no materials dedicated to this theory yet, but you can search related reports in the CampusDown library (Korean).

Find more reports · Search '다운증후군' on CampusDown →
Klinefelter SyndromeKlinefelter syndrome explained: the 47,XXY sex chromosome condition in males, its symptoms such as small testes, low testosterone, infertility and language difficulties, karyotype diagnosis, testosterone therapy and support.🩺 Nursing & HealthCytokine Release SyndromeCytokine release syndrome (CRS) explained: a systemic inflammatory response causing fever, hypotension and hypoxia. Causes such as CAR-T and bispecific antibodies, the role of IL-6, ASTCT grading, tocilizumab and steroids.🩺 Nursing & HealthDumping SyndromeDumping syndrome explained: early and late dumping after gastric or bariatric surgery, symptoms and mechanisms, diagnosis including the Sigstad score, dietary measures and drug treatment.🩺 Nursing & HealthFragile X SyndromeFragile X syndrome explained: the FMR1 CGG repeat expansion behind the most common inherited intellectual disability, X-linked inheritance, cognitive, behavioural and physical features, DNA testing and educational support.🩺 Nursing & Health

You may also like

Brown v. Board of Education (1954)Brown v. Board of Education (1954) summary: the case, Chief Justice Warren's unanimous ruling, why 'separate but equal' fell, and what happened after.⚖️ LawIntestate SuccessionWho inherits when someone dies without a will: how U.S. intestacy statutes rank spouses, children and other relatives, how per stirpes works, and how Korea's Civil Act sets heirs, shares and representation.⚖️ LawThe Rule of LawWhat is the rule of law? Its meaning and history from Magna Carta to United States v. Nixon, Dicey and Fuller's principles, and how it differs from rule by law.⚖️ LawCommon Law vs. Civil LawCommon law vs. civil law: how the two legal families differ on sources of law, precedent, trials and judges, and where Korea's mixed system fits between them.⚖️ Law

This article was last updated on October 15, 2026. It is based on widely recognized original works and textbooks; when citing it in a paper, please check the original sources listed in the references.