Why is it that kids with down syndrone all look the same?

Question

I'm not making fun of their condition, I would like to just know why. There is a kid who goes to my school who has it and I feel really bad for him. And I saw a boy and girl last month while on vacation who looked exactly the same like the kid at my school.

Answer 1

It's a chromosomal mistake. One of the chromosomes in each of their cells copied twice instead of the usual once, leaving three chromosomes to function in the place of two. So there's extra "information" in their genetic code. The areas of the brain affected by this partly control facial motions and social reactions. It's just the way the "code" is interpreted...the cells don't know to cut out a part that says "continue" even if its repeated multiple times. So the instructions come out different from average. Since it's the same chromosome recopied every time, they tend to look a lot alike, although individual features and severity will vary.