Down Syndrome

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Down syndrome is the most common autosomal chromosome abnormality.

Incidence of 1:600-1:800.

Mental retardation accompanies Down syndrome, with IQ between 20-80.

Children frequently have a

Between 30-50% of children have congenital heart disease



The Case of...

a simple case introducing clincial presentation and calling for a differential diagnosis. To get students thinking.

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Causes and Risk Factors

Risk is ~1/2000 for a 20 year old mother, ~1/100 for a 40 year old mother, and ~1/30 for a 45 year old mother.

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Signs and Symptoms

no one feature that all children with Down's syndrome have, and no one feature distinguishes Down's children from others

  • history
  • physical exam


  • recurrent infections
  • 15-20x increase in leukemia
  • male infertility
  • IQ: 25-50
  • dementia in 100% of people over 45


Physical Exam


Eyes: upslanted epicanthal folds, speckled iris (Brushfield spots), refractive errors, strabismus

Ears: low-set, small, overfolded upper helix

Face: protruding tongue, large cheeks, low, flat nasal bridge

Skin: excess nuchal skin

MSK: short, joint hyperflexibility, atlantoxaial instability

GI: duodenal, esophageal, anal atresia, TE fistula, Hirschprung disease, chronic constipation

CV: 40%, especially AVSD

GU: cryptorchidism, small penis

CNS: hypotonia

hands: palmar (Simian) crease

  • short stature, hypothyroidism
  • palmar crease


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  • lab investigations
  • diagnostic imaging
  • screening

Lab Investigations

Diagnostic Imaging


Thyroid function should be assessed

Eyes in newborn period: strabismus and cataracts


Lateral flexion-extension of cervical spine for instability

Heart (50% congenital haert defects)


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Differential Diagnosis

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Consequences and Course

life expectancy is ~60 without CHD

increased mortaility due to infections, CHD, malignancy

congenital heart disease is present in 40% of people with Down's Syndrome.

Common problems include:

Gastrointestinal conditions include esophageal and duondenal atresia, as well as celiac disease.

Infants can have increased length of physiologic jaundice, polycythemia, and a temporary leukocytosis.


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Resources and References

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Topic Development




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