20 week scan

Shadelle
I had my 20 week anatomy scan today, I'm currently 21 weeks. We have already done the Harmony genetic scan and everything came back great and we know we are having a little boy. Today after the ultra sound the doc showed us that our son's big toe and following one have a slight gap inbetween them. He said it's called Sandal toe and is a soft marker for Downs. This is the only thing out of the ordinary he saw, should I be worried? Has anyone had a similar experience?