Down syndrome, also known as Trisomy 21, is a genetic condition caused by the presence of an extra copy of chromosome 21. This additional genetic material affects physical and intellectual development, leading to a wide range of abilities and health concerns. Down syndrome is one of the most common chromosomal disorders, occurring in approximately 1 in every 700 live births.
Down syndrome occurs due to a genetic error during cell division. There are three types:
1. Trisomy 21 (95%): Every cell in the body has three copies of chromosome 21.
2. Translocation (4%): Part of chromosome 21 becomes attached (translocated) to another chromosome.
3. Mosaicism (1%): Some cells have an extra chromosome 21, while others have the typical two copies.
It is not caused by anything the parents did before or during pregnancy, although advanced maternal age increases the risk.
Individuals with Down syndrome may share some physical traits, though not all people will have the same features:
• Flattened facial profile
• Almond-shaped eyes with an upward slant
• Short neck
• Small ears and hands
• Low muscle tone (hypotonia)
• Short stature
They may also have mild to moderate intellectual disability and delayed developmental milestones.
Associated Health Conditions
People with Down syndrome are at increased risk for certain medical conditions, including:
• Congenital heart defects
• Hearing and vision problems
• Thyroid dysfunction
• Respiratory issues
• Gastrointestinal abnormalities
• Leukemia
• Alzheimer’s disease (early onset)
Prenatal Diagnosis:
• Screening tests: Blood tests and ultrasound during the first or second trimester.
• Diagnostic tests: Chorionic villus sampling (CVS) or amniocentesis confirms the diagnosis.
Postnatal Diagnosis:
• Based on physical appearance and confirmed with a chromosomal karyotype blood test.
Early support significantly enhances development. Key services include:
• Physical therapy: Improves motor skills, posture, and strength.
• Speech and language therapy: Helps with communication and language development.
• Occupational therapy: Supports daily living skills and independence.
• Educational support: Tailored learning strategies to meet cognitive needs.
With proper care, education, and inclusion, people with Down syndrome can:
• Attend school
• Work in supported or independent settings
• Live semi-independently or with family
• Develop meaningful relationships and participate actively in the community
Lifespans have increased dramatically over the past few decades, with many individuals living into their 60s and beyond.
