Help: can anyone answer my questions on gene

[S957325 at cuhk.hk]

Dear everybody

I want to know what is gene and something about genetic.  In recent years, 
there have been a lot of genetic dieases being discovered.  Will eveyone in 
the world suffer from this kind of dieases?  

In such an advanced world, can any medicine cure the illness??

I hope the one who have knowledge on this field can answer my questions!

Thank you very much!

Linda Au