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Down Syndrome

Down Syndrome

Down syndrome is a genetic disease resulting from a chromosomal abnormality. An individual with Down syndrome inherits all or part of an extra copy of Chromosome 21. Symptoms associated with the syndrome include intellectual disability, distinctive facial characteristics, and increased risk for heart defects and digestive problems, which can range from mild to severe. The risk of having a child with Down syndrome rises with the mother's age at the time of conception.

Down Syndrome
Images and animations are courtesy of the National Human Genome Research Institute's Talking Glossary (

Materials for Down Syndrome


Chromosomes and Cytogenetics

Description: Detailed information on chromosome structure, analysis, and disorders

Down Syndrome

Description: An overview on Down syndrome

Down Syndrome

Description: Information on the cause, symptoms, and diagnosis of Down syndrome

Down Syndrome

Description: Questions answered by GARD Information Specialists, links to resources, information about research, conferences, genetic testing, and genetic services

Down Syndrome Fact Sheet

Description: A fact sheet on Down syndrome

Kids Health: Down Syndrome

Description: Down syndrome information written for kids and links to information on related topics

Learning About Down Syndrome

Description: An overview on Down syndrome

What Is a Chromosome Disorder?

Description: A chromosome disorder results from a change in the number or structure of chromosomes.

What Is Down Syndrome?

Description: Down syndrome is a genetic disorder caused by the presence of all or part of an extra copy of chromosome 21.


Make a Karyotype

Description: Practice identifying chromosomes in a karyotype by playing this interactive matching game.

Interactive Tutorials

Your Genes Your Health - Down syndrome

Description: An interactive Web site exploring Down syndrome.

Teacher Resources

Analyzing Chromosomes (PDF 7,056.8 KB, Lesson Plans/Lesson Activities)

Description: Students learn about chromosome analysis by completing a partial karyotype and assess the karyotype for anomalies. Students practice sharing bad news to parents.



Description: Milestones features four families, each with a son or daughter with Down syndrome.


Description: An animation illustrating normal cell division, followed by cell division with a nondisjunction event.