As previously said, the greatest amount of genetic material, generates on persons affected by the Down's Syndrome health problems that are typical of this syndrome and are identified into specific physical and mental characteristics.
The features that distinguish persons affected by the Down's Syndrome are many and can not occur all at once on the same person.
There are not reports that groups and/or make the characteristics depending on each other.
Some of them, however, are very common and are observed on a large population of individuals.

Small stature is one of the most common characteristic and is present in the 100% of subjects, with the mental retardation that is present in the 99.8% pratically in all subjects.
The atypical Fingerprints are present in the 90% of subjects.
The separation of the abdominal muscles, the ligaments flexible and hypotonia in the 80%.
The Brachicefalia (skull wider than long), the small genitals and large eyelids present in the 75%.
The shorter extremity and Oval Palate are present nearly in the 70%.
Low set and rounded ears, small teeth and nose flattened in the 60%
The Clinodactyly (the phalanx misaligned), the umbilical hernia, the short neck and short hands are present nearly in the 50%.
The congenital Heart disease and single transverse palmar fold in the 45%.
The Macroglossia (Big Tongue) and epicanthal folds (folds around the eyes) in the 42%.
Strabismus in the 40%.
Stains of Brushfield (spots in the iris eye) in the 35%.

All these features without distinction, are able to high variability, since it depends on how much affect on that feature the greatest amount of genetic material.