Additional CPN1 variants were recently reported in HAE families in combination with other alleles, for example, a NM_001308.2:c.931T>C;p.(Cys311Arg) variant, predicted to be deleterious, combined with NM_000301.3(PLG):c.988A>G;p.(Glu330Lys) in a patient with HAE with plasminogen activation,43 and a NM_001308.2:c.1219G>A;p.(Glu407Lys) variant combined with TLR4, MASP1, PLAU, and MPO variants in a patient with HAE of unknown cause.26 Here, MPO is linked to hereditary angioedema.