Down syndrome, also known as trisomy 21, is one of the most common chromosomal disorders, occurring in approximately 1 in 700 live births. The condition results from a full or partial extra copy of chromosome 21. 

People with Down syndrome typically have distinctive physical features and exhibit: 

• Mild to moderate intellectual disability 

• Delays in reaching developmental milestones 

• Increased risk of certain medical conditions 

With advances in medical care, early intervention, and societal acceptance, people with Down syndrome can achieve significant developmental progress and lead active, healthy lives. Life expectancy for people with Down syndrome has increased from 25 years in the 1980s to 60 years and beyond today. 

There are three types of Down syndrome: 

1. Trisomy 21 (95% of cases): Every cell in the body has an extra chromosome 21. 

2. Mosaic Down syndrome (2% of cases): Only some cells have the extra chromosome 21. 

3. Translocation Down syndrome (3% of cases): Part of chromosome 21 attaches to another chromosome. 

The exact cause of the chromosomal error is unknown, but maternal age is a known risk factor. The likelihood of having a child with Down syndrome increases as a woman ages, particularly after age 35. 

Developmental Delays 

• Delayed achievement of milestones such as sitting, walking, and speaking 

• Difficulties with attention, memory, and learning 

Intellectual Disability 

• Mild to moderate intellectual disability 

• Affects cognitive functions such as reasoning, problem-solving, and adaptive behavior 

Physical Features 

• Distinctive facial features:  

  • Flattened facial profile 

  • Almond-shaped eyes that slant upward 

  • Small ears 

  • Short neck 

  • Small nose 

• Single deep crease across the palm 

• Small hands and feet 

• Short stature 

Low Muscle Tone (Hypotonia) 

• May lead to delayed motor development 

• Difficulties with coordination and strength 

Medical Conditions 

People with Down syndrome have an increased risk of certain medical conditions: 

• Congenital heart defects (50% of cases) 

• Gastrointestinal issues (12% of cases) 

• Thyroid disorders (15% of cases) 

• Hearing loss (75% of cases) 

• Vision problems (60% of cases) 

• Sleep apnea (50-75% of cases) 

People with Down syndrome often have unique social and emotional traits, including: 

• Strong empathy and social awareness 

• A generally happy and affectionate disposition 

• Some degree of challenges in emotional regulation and social skills 

Social inclusion and community support play crucial roles in the well-being of people with Down syndrome. Participation in inclusive educational settings, community activities, and social groups can significantly enhance their quality of life and development. 

Down syndrome can be diagnosed during pregnancy or after birth through a combination of screening and diagnostic tests: 

Prenatal Screening 

• Non-invasive tests such as ultrasound, maternal blood tests, and cell-free DNA screening indicate the likelihood of Down syndrome (though are not definitive) 

• Accuracy varies with these tests; there is an 80-95% detection rate with a 5% false positive rate 

Diagnostic Tests 

• Provide a definitive diagnosis by analyzing the baby's chromosomes 

• Test options include: 

  • Amniocentesis (99% accuracy) 

  • Chorionic villus sampling (CVS) (98-99% accuracy) 

  • Percutaneous umbilical blood sampling (PUBS) (99% accuracy) 

Postnatal Diagnosis 

• Physical examination 

• Chromosomal analysis (karyotype) confirms the presence of extra chromosome 21 

• Nearly 100% accurate 

Management of Down syndrome focuses on addressing the person’s developmental, educational, and medical needs.  

Early Intervention Programs 

• Provide therapies and educational support from infancy 

• Help with developmental delays 

• Include speech, physical, and occupational therapies 

Special Education 

• Tailored educational plans (individualized education programs or IEPs) 

• Accommodate the child's learning needs 

• Provide appropriate supports in school settings 

• Focus on inclusive education where possible 

Medical Care 

• Regular monitoring and treatment for associated health conditions 

• Routine check-ups and screenings 

Speech and Language Therapy 

• Assist with communication skills 

• Focus on language development, articulation, and social communication 

Occupational Therapy 

• Improve fine motor skills and sensory processing 

• Enhance ability to perform daily living tasks 

Physical Therapy 

• Develop gross motor skills 

• Improve strength and coordination 

Family Support 

• Provide education, resources, and counseling to families 

• Help families support their child's development and well-being 

Support for the Transition to Adulthood 

• Vocational training and employment support 

• Life skills education for independent or supported living 

• Continuing education opportunities