Down Syndrome
A genetic condition caused by an extra copy of chromosome 21, causing learning disability and some health problems.
Quick Summary
Characteristic facial features, low muscle tone, learning disability and delayed development; some have heart or thyroid problems.
Early intervention, therapies, education support and regular health checks.
Higher maternal age, though it can occur at any age.
Overview
Down syndrome isn't caused by anything parents did. People with Down syndrome can lead full lives with support.
Screening and diagnostic tests in pregnancy can detect it.
Symptoms
Learning disability
Mild to moderate.
Low muscle tone
Floppy babies.
Heart defects
In about half of babies.
Other problems
Thyroid, hearing and vision issues.
Causes & Risk Factors
Biological Causes
An extra copy of chromosome 21 (trisomy 21).
Key Risk Factors
- Maternal age Risk rises with age.
- Previous child With Down syndrome.
- Translocation Rarely inherited.
Management & Treatment
01. Early intervention
Physio, speech and occupational therapy.
02. Health checks
Heart, thyroid, hearing and vision.
03. Education
Inclusive schooling and support.
Frequently Asked Questions
Can it be detected in pregnancy?
Can people with Down syndrome work?
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Down Syndrome(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Down's syndrome(opens in a new tab) · NHS