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			          Down Syndrome: Causes, Types and Symptoms - Healthline
			           
 Down syndrome (sometimes called Down's syndrome) is a condition in which a child is born with an extra copy of their 21st chromosome (hence its other name, Trisomy 21). This causes physical and mental developmental delays and disabilities. http://www.healthline.com/health/down-syndrome#Overview1
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			          Down Syndrome, Topic Overview - WebMD
			           
 Down syndrome is a set of physical and mental traits caused by a gene problem that happens before birth. http://www.webmd.com/children/tc/down-syndrome-topic-overview#1
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			          Down's Syndrome - NHS Choices
			           
 Down's syndrome, also known as Down syndrome, is a genetic condition that typically causes some level of learning disability and characteristic physical features. http://www.nhs.uk/conditions/Downs-syndrome/Pages/Introduction.aspx
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			          What Is Down Syndrome? - National Down Syndrome Society
			           
 Down syndrome occurs when an individual has a full or partial extra copy of chromosome 21. http://www.ndss.org/Down-Syndrome/What-Is-Down-Syndrome/
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			          Down Syndrome - Kid's Health
			           
 Down syndrome is a condition in which extra genetic material causes delays in the way a child develops, both physically and mentally. http://kidshealth.org/en/parents/down-syndrome.html
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			          Down Syndrome: Symptoms, Causes, Diagnosis and Treatment - WebMD
			           
 Down syndrome is a lifelong condition in which a person is born with distinct physical features and some degree of cognitive disability. http://www.webmd.com/children/tc/down-syndrome-topic-overview
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			          Down Syndrome: Causes, Types and Symptoms
			           
 Down syndrome is the most common genetic condition in the United States. It causes physical and mental developmental delays and disabilities. http://www.healthline.com/health/down-syndrome
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			          Down Syndrome - Mayo Clinic
			           
 Down syndrome - Comprehensive overview covers causes, risk factors and diagnosis of this genetic disorder. http://www.mayoclinic.org/diseases-conditions/down-syndrome/basics/definition/con-20020948
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			          Down Syndrome - March of Dimes
			           
 Down syndrome is a chromosomal disorder that causes intellectual disability and other health problems. Get the facts on treatment options for your child. http://www.marchofdimes.org/complications/down-syndrome.aspx
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			          Down syndrome Causes - Mayo Clinic
			           
 Down syndrome - Comprehensive overview covers causes, risk factors and diagnosis of this genetic disorder. http://www.mayoclinic.org/diseases-conditions/down-syndrome/basics/causes/con-20020948
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			          Down Syndrome Information Alliance - DSIA
			           
 The Down Syndrome Information Alliance provides support and resources to empower individuals with Down syndrome, their families, and our community. http://downsyndromeinfo.org
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			          Down's Syndrome: Signs of Down's Syndrome and Test. - Patient
			           
 Down's syndrome is a genetic chromosome problem. Someone with Down's syndrome has an extra copy of chromosome 21 in the cells of their body. http://patient.info/health/downs-syndrome-leaflet
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			          Down Syndrome Issues and Information
			           
 Down Syndrome Issues and Information is an extensive series of comprehensive reference resources examining issues for people with Down syndrome from birth to adulthood. https://www.down-syndrome.org/information/