Help please 16 week scan

Jessie • married 2 😇 babies and 2 beautiful little girl. And baby 3 on the way.

So when I had my ultrasound the other day I was 16 weeks and they said they seen a bright spot on my little boy's heart the doctor come in and explained that could be a sign of down syndrome but the rest of his scans come out normal I'm waiting on the results from my blood test. To know for sure has anyone else experienced this