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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/