Thank you very much for your support. Today we had our four marker screen test and it was clear! Papp-a result is the only marker which worries us and our doctor. As you mention pregnancy makes us learn a lot about all kinds of related medical conditions. I have been searching on the internet for about three days. We will be visiting another doctor on Saturday and maybe amniocentesis will be applied. We will be hoping for good results...
I have no experience with a high PAPP-A level, but I do wish you all the best. The only other thing I would add is that pregnancy has made us all science experiments and for every scary test result, there is another test that can clarify the first one. Try not to worry until you have to.