By Sarah McClure
Disease
Physical disorder
Genetic disorder
Illness
The United States
England
Russia
Canada
4,000
400,000
400
40,000
Yes
No
Rarely
I don't know
1
2
3
4
3rd chromosome
23rd chromosome
18th chromosome
21st chromosome
Betsy Smith
Hannah Hannum
Heather Dale
Rebecca Miller
Glee
Pretty Little Liars
The Office
Shake it Up