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Down Syndrome Day – March 21 Published: ()

Down syndrome, a chromosomal abnormality, is one of the most common congenital anomalies (or birth defects) worldwide, and the most common one in Canada. Diagnoses are most often made during pregnancy and the first year of the child’s life. Children with Down syndrome present with well-defined physical characteristics. They often experience intellectual delay and are at an increased risk for several medical conditions. Congenital heart defects and respiratory infections are the most frequently reported causes of death in children and young adults with Down syndrome. Childhood leukemia is commonly associated with Down syndrome. However, the life-expectancy of individuals with Down syndrome has improved over time.

The Public Health Agency of Canada's Canadian Congenital Anomalies Surveillance System (CCASS) monitors and reports on national estimates and trends of congenital anomalies including Down syndrome. The CCASS is part of the Canadian Perinatal Surveillance System (CPSS). The CPSS is a national health surveillance program aiming to contribute to the improved health of pregnant women, mothers and infants in Canada.


Down syndrome occurs due to the presence of an extra chromosome 21. [Gardner RJM, Sutherland GR. Chromosome Abnormalities and Genetic Counseling. 3rd Ed. Toronto: Oxford University Press; 2004. p. 249-252]

1 in 750

One in every 750 live born babies in Canada is diagnosed with Down syndrome. [Down Syndrome Surveillance in Canada, 2005-2013]


In the last decade, the average rate of Down syndrome in Canada has been 15.8 per 10,000 total births. [Down Syndrome Surveillance in Canada, 2005-2013]


Women 35 years of age and older are more likely to have a baby with Down syndrome than younger women. [Down Syndrome Surveillance in Canada, 2005-2013]


Despite the increased risk to older women, there are more babies with Down syndrome born to younger women (aged 34 and younger). That can be explained by the fact that 52% of total births occur in women under 35 years due to higher fertility rates in younger women. [Down Syndrome Surveillance in Canada, 2005-2013]

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