why do down syndrome babies have the same appearance although they belong to different parents?

Answer 1

Down syndrome is due to trisomy 21, or an extra 21st chromosome. Because there is an extra chromosome, there are several genetic implications that lead to developmental changes.

Everyone follows the same general pattern as they go from embryo, to blastocyst, fetus, and then the person walking down the street, but the extra chromosome changes the timing of the cell divisions that give rise to a person in a predictable manner that gives people with down syndrome physical features that give them the "same appearance."

Answer 2

Just as Tizzy said, they certainly don't all look the same, although many share similar facial characteristics as a result of the triplication of the 21st chromosome and the genes found on that chromosome.

I know LOTS of children with Down syndrome (babies, toddlers, etc) and they all look very different. If you really look objectively, you will see that they probably resemble their family members more than each other.

Answer 3

They share with each other the same chromosomal arrangement, which is different from their parents. The extra chromosome is associated with certain facial characteristcs.

The individuals of course share with their parents lots of appearance clues, like eye and hair colour.

Answer 4

They all have a genetic disposition to the facial features that we are familiar with.
It affects all parts of the body including the brain which is usually a trait that may be most noticeable.

Answer 5

they dont all look the same!!!!!! ????!!!!! what a silly thing to say !!! they are all individual, and all look individual!! ok they have certain facial features that are similar due to the condition, but i can honestly say I have never seen 2 Downs syndrome babies look the same!