About 1/1000 to 1/500 males have Klinefelter's syndrome.

there are approxmately 1/4 million families in the united states affected by down syndrome.

1 in every 1,000 babies that is born. 1 is the Down syndrome and 1,000 is the people that dont.

No, they are nondisjunctions of the sex chromosomes (since in Turner syndrome you only have 1 sex chromosome and in Klinefelter syndrome you have 3).

Marfan syndrome is found in 1 in every 5,000 - 10,000 births. If one of your parents has Marfan syndrome, you have a 50% chance of having Marfan syndrome.