What can a small nasal bone in 22 week scan mean apart from down syndrome ?

Talk with the Ob-Gyn: Depending upon ethnic group and other factors, some babies will not show bone formation in the nasal bridge by 22 weeks. It is believed that having a nonossified nasal bone between 15 and 22 weeks increases the Down syndrome risk, especially in women with high risk factors. But, it is statistics (look at all data), so some normal babies and some with other syndromes can have the same finding.