Good evening! Can you tell me if anyone has ever had this or maybe heard…

Good evening! Can you tell me if anyone has ever had this or maybe heard of Marker (HX) chromosomal anomaly and yet the child was born normal? Today the gynecologist said that it's possible that Down syndrome will be present (he also added that healthy babies can be born with such diagnosis, it will be clear at birth ?) We take the baby at 33 weeks.