Sometimes you see people who look retarded, like they have Down's Syndrome (face is odd shaped, eyes crossed, etc.), but then they actually are not that retarded. Like they can actually carry on a normal conversation with people, etc.
What is that called?
Most Helpful Girl
Sounds like that could be 'Mosaic Down Syndrome'.
Full-on down syndrome occurs because of what is known as 'trisomy 21', or there being 3 copies of chromosome 21 in every cell. That cell-error in Down Syndrome occurs prior to fertilization of the egg, meaning hat every cell in this person's body will have the extra copies of chromosome-21.
In Mosaic Down syndrome, this error occurs later on in development, after fertilization. This, in turn, will mean that an individual with MSD will have two lines of cells. One line of cells may have cells with the extra chromosome-21, but their other line of cells may be perfectly normal. This means that people with MSD will often have fewer or milder symptoms than those with full-on Down's.1
Most Helpful Guy