Down syndrome, also known as Trisomy 21, is a genetic condition caused by the presence of an extra copy of chromosome 21. It affects physical growth, intellectual development, and overall health. The condition is one of the most common chromosomal abnormalities worldwide and remains an important topic under public health, genetics, and inclusive development.
Key Facts for Prelims
| Aspect | Details |
|---|---|
| Definition | A genetic disorder caused by the presence of an extra (third) copy of chromosome 21, leading to developmental and health-related differences. |
| Type of Genetic Change | Chromosomal aneuploidy (specifically trisomy). |
| Cause | Nondisjunction during cell division leading to an extra chromosome 21 in all or some cells. Not related to parental behavior, environment, or lifestyle. |
| Diagnostic Methods | – Prenatal screening: Blood tests, ultrasounds, and invasive tests like amniocentesis or chorionic villus sampling (CVS). – Postnatal diagnosis: Karyotype test to confirm the presence of an extra chromosome. |
| Prevalence (India) | Approximately 1 in 800 to 1,000 live births. With about 25 million annual births, this equals tens of thousands of affected infants each year. |
| Health Considerations | Common issues include congenital heart defects (seen in up to 50% of cases), hypothyroidism, hearing and vision impairments, gastrointestinal anomalies, and susceptibility to infections. |
| Life Expectancy | Improved due to better healthcare. Individuals without major heart defects show significantly higher survival rates (up to 79% survival to age 30). |
| Risk Factors | Advanced maternal age increases risk, but the condition can occur at any maternal age. |
| Developmental Aspects | Individuals may show delayed growth and learning differences, but targeted interventions—speech, occupational, and physical therapy—significantly improve outcomes. |
| Support and Interventions | Early detection, regular health screening, inclusive education, and community-based support improve quality of life. |
| Awareness and Advocacy | March 21 is observed globally as World Down Syndrome Day to promote inclusion, awareness, and rights of individuals with Down syndrome. |
Ethical and Social Dimensions
- Down syndrome is not a disease to be “cured” but a condition requiring lifelong support and respect for individual dignity.
- Reducing stigma, providing equitable healthcare, and ensuring inclusive education remain key public policy objectives.
- Ethical debates around prenatal testing and selective termination underscore the importance of informed consent and non-discrimination.
India’s Context
India witnesses a large number of children born annually with chromosomal abnormalities, including Down syndrome. Although early detection programs have expanded, access to screening and postnatal developmental support remains uneven. Initiatives such as the release of guidebooks for parents and awareness programs by medical institutions aim to bridge this gap.
Reference: The Hindu
