What is Down Syndrome?

Down syndrome is a naturally occurring genetic condition in which a child is born with an extra copy of chromosome 21. As a result, certain genes on chromosome 21 are over-expressed, impacting an individual in many ways. Down syndrome affects each person differently; no individual is likely to exhibit all the characteristics commonly associated with Down syndrome.

Common Physical Characteristics: 

  • Flat bridge of the nose
  • Simian crease on the palms
  • Extra space between the big toe and adjacent toe
  • An extra fold of skin around the eyes
  • Widely spaced and upward-slanting eyes
  • Straight hair
  • Structural differences in the mouth and ears
  • Short stature

Common Developmental Concerns: 

  • Neurological and cognitive differences
  • Mild to moderate intellectual delays
  • Behavioural issues
  • Speech deficits
  • Memory impairment
  • Higher prevalence of autism spectrum disorder

Common Health Concerns: 

  • Heart defects
  • Vision and hearing impairment
  • Thyroid problems
  • Respiratory issues
  • Sleep disorders
  • Mental health issues
  • Gastrointestinal issues
  • Dental problems
  • Childhood leukemia
  • Early-onset Alzheimer’s and dementia

Did You Know?

Approximately 1 in 800 babies born in Canada has Down syndrome. Genetically, there are three types of Down syndrome:

Trisomy 21: The most common type of Down syndrome, in which the person has a complete extra copy of the 21st chromosome

Translocation: A rarer type of Down syndrome, in which an additional full or partial copy of chromosome 21 is attached to a different chromosome (2-3% of people with Down syndrome)

Mosaicism: The rarest type of Down syndrome, in which only some cells in the body have a full extra copy of the 21st chromosome, and the rest of the cells are typical (1% of people with Down syndrome)

Though people with Down syndrome may share some common characteristics, each is a unique individual. Thanks to medical research, a better understanding of the condition, and shifting societal norms, people with Down syndrome can expect to live long, happy lives. We must continue to work together to build a world that values and empowers people with Down syndrome, fostering economic, social, and individual inclusion throughout their lives.

DSRF Resources

A Quick Guide to Down Syndrome for Parents

The T21 Difference: Learning Profiles of Students with Down Syndrome