Yes, Marfan syndrome is autosomal dominant.
people
If one allel is dominant and the other is reccesive then the individual is said to be heterozygous. Sorry about the spelling.
Yes, Downs Syndrome is found in USA
Yes, people with Downs Syndrome can get depressed.
A few are.
It is dominant in females and males die before they can pass it on.
Heterozygous means that it carries both dominant and recessive traits (as opposed to homozygous which carries only one) - the dominant trait is the one which is expressed (phenotype). A heterozygous trait can be expressed as Rr - "R" the dominant trait and "r" the recessive trait.
5
Trisomy 21
Low amniotic syndrome usually an indication of downs syndrome.
autosomal dominant.......... i think