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Down syndrome: Overview of prenatal screening

Geralyn M Messerlian, PhD
Glenn E Palomaki, PhD
Section Editor
Louise Wilkins-Haug, MD, PhD
Deputy Editor
Vanessa A Barss, MD, FACOG


Early detection of pregnancies at high risk for trisomy 21 (Down syndrome) is the primary target of prenatal aneuploidy screening since this syndrome is the most common autosomal trisomy among live births. Because biochemical-marker screening for Down syndrome involves measuring levels of the same markers that perform well for detecting trisomy 18 (Edwards syndrome, the second most common autosomal trisomy among live births), biochemical-marker screening tests provide risk assessment for both chromosomal abnormalities. Some screening tests also provide risk assessment for trisomy 13 (Patau syndrome). Because both the birth prevalence and long-term survival are much higher for Down syndrome than for trisomies 18 and 13, this topic will focus on Down syndrome.

Issues related to prenatal screening for Down syndrome will be reviewed here. The clinical characteristics, medical care, and prognosis for children with these syndromes are discussed separately:

(See "Down syndrome: Clinical features and diagnosis".)

(See "Down syndrome: Management".)

(See "Congenital cytogenetic abnormalities", section on 'Trisomy 21 (Down syndrome)'.)

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Literature review current through: Nov 2017. | This topic last updated: Aug 07, 2017.
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