Down syndrome

Last reviewed: April 2018

Last updated: December 2017

Summary

Most common genetic cause of cognitive or intellectual disability, with a prevalence of 1 in 691 births.

Characteristic physical features include brachycephaly with a flat occiput; epicanthal folds and upslanting palpebral fissures; Brushfield spots in the iris; low nasal bridge; low-set ears; broad neck; and small hands with transverse crease.

Higher frequency of congenital and acquired medical conditions, including congenital heart defects, audiologic, vision, GI, hematologic, and thyroid issues.

Global developmental delay, variable IQ ranging from mild to moderate intellectual disability, and age-related pattern of neurobehavioral phenotype.

Early interventional therapies (e.g., speech therapy, physical therapy, occupational therapy) and individualized educational programs/resources are essential to maximize the potential of a person with Down syndrome.

Definition

Down syndrome (DS), or trisomy 21, is the most common genetic form of intellectual disability, occurring in 1 in 691 births. [1] In addition to having characteristic physical features, short stature, and hypotonia, individuals with DS have a distinctive cognitive and behavioral profile. They also have a higher frequency of associated medical conditions, including congenital heart defects, and gastrointestinal, thyroid, hematologic, audiologic, and visual abnormalities.

History and exam

Key diagnostic factors

common physical exam features
hypotonia
congenital heart disease
gross motor delay
language delay
cognitive disability
hearing loss
autism spectrum disorder

Full details

Other diagnostic factors

congenital GI disorder
constipation
feeding difficulty
behavioral difficulties

Full details

Risk factors

advanced maternal age
previous child with DS
parental karyotype with a translocation

Full details

Diagnostic investigations

1st investigations to order

chromosomal karyotype

Full details

Investigations to consider

echocardiogram
abdominal x-ray
hearing test
TFTs
hemoglobin
vision exam
dental exam
developmental evaluation
psychoeducational evaluation
total IgA and antitissue transglutaminase antibodies
polysomnography
cervical neck x-rays

Full details

Treatment algorithm

ACUTE

newborns

ONGOING

children

Contributors

Authors VIEW ALL 

Kishore Vellody, MD

Associate Professor of Pediatrics

Medical Director

Down Syndrome Center of Western Pennsylvania

Children’s Hospital of Pittsburgh

Pittsburgh

Disclosures

KV is Vice President of the Executive Committee of the Board of the National Down Syndrome Congress.

Acknowledgements

Dr Kishore Vellody would like to gratefully acknowledge Dr Jeannie Visootsak, the previous contributor to this monograph. JV declares that she has no competing interests.

Peer reviewers VIEW ALL 

Nirupama S. Madduri, MD

Assistant Professor

Developmental-Behavioral Pediatrics

Vanderbilt University School of Medicine

Nashville

Disclosures

Not disclosed.

W. Carl Cooley, MD

Medical Director

Crotched Mountain Foundation

Medical Director

Center for Medical Home Improvement

Adjunct Professor of Pediatrics

Dartmouth Medical School

Greenfield

Disclosures

WCC declares that he has no competing interests.

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Down syndrome

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

newborns

children

Contributors

Authors VIEW ALL 

Kishore Vellody, MD

Disclosures

Acknowledgements

Peer reviewers VIEW ALL 

Nirupama S. Madduri, MD

Disclosures

W. Carl Cooley, MD

Disclosures

Differentials

Guidelines

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