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GTR Home > Conditions/Phenotypes > Trisomy 21

Summary

A chromosomal abnormality consisting of the presence of a third copy of chromosome 21 in somatic cells. [from NCI]

Clinical resources

Practice guidelines

  • ACMG ACT, 2021
    American College of Medical Genetics and Genomics Noninvasive Prenatal Screening via Cell-Free DNA ACT Sheet, Trisomy 21/Down syndrome: Positive Cell Free DNA Screen, 2021

Consumer resources

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