Rate of sequence variations in type 1 VWD studies. This graph shows rates of sequence variations discovered in subjects with type 1 VWD in each of 4 large VWD studies. The first column (in black) represents the UK study subjects with VWF:RCo <50 IU/dL,¹⁷  the second column (in light grey) represents the MCMDM-1VWD study type 1 subjects with VWF:Ag ≤45 IU/dL,¹⁵  the third column (in white) represents the Canadian type 1 VWD study subjects with VWF:Ag between 5 and 50 IU/dL,¹⁶  and the fourth column (in dark grey) represents the US Zimmerman Program study type 1 subjects with VWF:Ag <40 IU/dL.¹⁸  The percentage of each group with sequence variations is shown at the top of each column.