What is Down syndrome?


It seems everyone has a slightly different definition of what Down syndrome is. In order to simplify the answer, it easiest to start with "What is a syndrome?". A syndrome is a collection of clinically recognizable symptoms. In the case of Down syndrome, those symptoms are easily observed by most people. They include:

  • Hypotonia - decreased muscle tone
  • Nuchal fold - Short neck, with excess skin at the back of the neck
  • Low nasal bridge and facial profile
  • Microcephaly - small head, including ears and mouth
  • Epicanthal fold - Upward slanting or almond-shaped eyes, often with a skin fold that comes out from the upper eyelid and covers the inner corner of the eye
  • Brushfield spots - white spots on the colored part of the eye
  • Wide, short hands with short fingers, especially the pinky finger
  • Single palmar crease - a single, deep, crease across the palm of the hand. previously referred to as "simian crease".
  • Sandal gap - A deep groove between the first and second toes
  • Bell-shaped chest

While this list is not comprehensive and not all individuals with Down syndrome have all of these symptoms, identification of any of  these characteristics at or near birth could indicate Down syndrome, but would require genetic testing to confirm. 

In addition to the observable characteristics, there are several other potential symptoms:

  • Congenital heart defect
  • Cleft palate
  • Strabismus (crossed or lazy eye)
  • Cognitive impairment
  • Atlanto-Axial Instability (excessive movement between 1st and 2nd vertebrae)