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Down syndrome in Infant/Neonate
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Down syndrome in Infant/Neonate

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Contributors: Bo Hoon Lee MD, Jamie Adams MD, Richard L. Barbano MD, PhD
Other Resources UpToDate PubMed


Down syndrome is a genetic disorder caused by trisomy of all or part of chromosome 21. Characteristic facial features include mild microcephaly, upslanting palpebral fissures, small nose with flat nasal bridge, small ears, and epicanthal folds. Other physical features include hypotonia, short neck with loose skin folds, single palmar creases, wide gap between first and second toes ("sandal gap"), and short stature. The degree of intellectual disability is variable.

Patients are at greater risk for atlantoaxial instability, hypothyroidism, constipation, gastroesophageal reflux disease, congenital heart disease, leukemia, impaired immune system, obstructive sleep apnea, and Alzheimer disease pathology / early-onset dementia. Life expectancy is 58.6 years. The major cause of early mortality is congenital heart disease.

For more information, see OMIM.


Q90.9 – Down syndrome, unspecified

41040004 – Complete trisomy 21 syndrome

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

  • Edwards syndrome (Trisomy 18)
  • Patau syndrome (Trisomy 13)
  • Wolf-Hirschhorn syndrome – Characteristic facial appearance includes flat nasal bridge and high forehead referred to as "Greek warrior helmet" appearance.
  • Angelman syndrome – Clinical clues may include severe language impairment, happy demeanor, hand-flapping, and ataxia.
  • Rett syndrome – This is almost exclusively seen in females and characterized by postnatal microcephaly and regression of language and purposeful hand movements in early childhood.
  • Williams syndrome
  • Smith-Lemli-Opitz syndrome
  • Cri-du-chat syndrome (5p minus [5p-] syndrome) – Infants often have a characteristic "catlike" cry.

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Last Reviewed: 04/06/2018
Last Updated: 12/04/2018
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Down syndrome in Infant/Neonate
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Down syndrome : Hearing loss, Hypotonia, Short stature, Developmental delay
Clinical image of Down syndrome
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