The extra chromosome 21 arrangement of Down syndrome
appears to be one of the most common genetic abnormalities known, occurring as frequently as 1 in every 800 to 1,000 births.
While Down syndrome is common, the symptoms an individual with Down syndrome experiences can vary. Some people may have several symptoms; others only a few. Some people experience severe symptoms of Down syndrome; others can have mild ones.
Characteristics of Down Syndrome Symptoms
There are estimated to be over 100 characteristics of Down syndrome. Common characteristics of Down syndrome can include:
- A flat facial profile
- An upward slant to the eye
- A short neck
- Abnormally shaped ears
- White spots on the iris of the eye (called Brushfield spots)
- A single, deep transverse crease on the palm of the hand
- Smaller than average size
- Exaggerated space between the first and second toe
- Poor muscle tone (called hypotonia)
- Joint looseness
- Broad feet with short toes
- Learning disabilities.