Their phenotype is the result after these genes have been “read” or expressed. I am quite perplexed by this connection. Slanted eyes, large tongue, small mandible, downward migrated ears, etc. Disease is both a social construct and a biomedical phenomenon. People with down syndrome are at increased risk for a range of other health conditions, including autism spectrum disorders, problems with hormones and glands, hearing loss, vision problems, and heart abnormalities. Theoretical example: a large tribe of japanese undergo a selection pressure for dark skin, and they develop it. This is why a mule is almost always sterile.
Facial effects down of syndrome. The front page of the internet. Infants readily learn to distinguish the faces they’ve been exposed to the most. I will not go into that in anymore detail. So of course you could have someone that has a similar feature set if they have the genes necessary and they express themselves during fetal development. Autoinfarcation of the spleen and susceptibility to encapsulated organism infection, etc).
Intellectual and developmental symptoms
So yes, they seem much nicer; they also get taken advantage of, or harmed, by others more often. Some may go to college, while others will need more day-to-day care.