▁males , ▁there ▁are ▁other ▁clin ical ▁criteria ▁that ▁can ▁be ▁used , ▁absent ▁these ▁characteristics , ▁to ▁make ▁the ▁diagn osis . ▁Pat ients ▁may ▁present ▁with ▁under develop ed ▁shoulder ▁bl ades , ▁short ened ▁and ▁ang ulated ▁lower ▁lim bs , ▁a ▁vert ically ▁orient ed ▁and ▁narrow ▁pel vis , ▁an ▁en larg ed ▁head , ▁an ▁unders ized ▁j aw , ▁c left ▁pal ate , ▁flat ▁nas al ▁bridge , ▁low ▁set ▁ears , ▁club ▁feet , ▁dis located ▁h ips , ▁ 1 1 ▁pairs ▁of ▁rib s ▁instead ▁of ▁ 1 2 , ▁or ▁b one ▁ab normal ities ▁in ▁the ▁neck ▁and ▁sp ine . ▁Res p ir atory ▁dist ress ▁can ▁be ▁caused ▁by ▁an ▁under develop ed ▁tra che a ▁which ▁col laps es ▁on ▁in hal ation ▁or ▁by ▁ins u fficient ▁rib ▁c age ▁development . ▁ ▁Gen et ics ▁ ▁C MD ▁is ▁caused ▁by ▁chrom os om al ▁ab normal ities , ▁generally ▁sp ont ane ously ▁ar ising ▁or ▁de ▁nov o ▁mut ations , ▁in ▁or ▁around ▁the ▁gene ▁SO X 9 ▁on ▁the ▁long ▁arm ▁of ▁chrom os ome ▁ 1 7 , ▁specifically ▁at ▁position ▁ 1 7 q 2 4 . ▁The ▁SO X 9 ▁gene ▁codes ▁for ▁a ▁protein ▁trans cription ▁factor ▁which , ▁when ▁expressed ▁at ▁the ▁emb ry onic ▁stage , ▁plays ▁an ▁important ▁role ▁in ▁determ ining ▁sexual ▁characteristics ▁and ▁greatly ▁influ ences ▁ske let al ▁development . ▁When