What is Down syndrome?
Down syndrome is a genetic disorder that causes mental retardation and physical defects. It is caused by the presence of an extra copy of chromosome number 21. This condition is called trisomy 21.
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Some of this content was developed by the University Centers for Excellence in Developmental Disabilities in CA (USC), MA (UMass Boston), IA (U of IA), KY (U of KY) and supported in part by the National Center on Birth Defects and Developmental Disabilities (NCBDDD) of the Center for Disease Control and Prevention through a cooperative agreement with Association of University Centers on Disabilities (AUCD). The opinions expressed are strictly those of the authors and do not necessarily reflect the opinions of the supporting organizations.
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