Related peptides with similar biological effects on ECs, i.e., the capacity to increase vascular permeability and local angioedema, include Lys BK, a decapeptide with an amino acid sequence identical to BK with lysine at position 10 formed by tissue kallikreins and desArg9BK, an octapeptide with an amino acid sequence identical to BK with Arg lacking at position 9 formed by several BK carboxypeptidases (Pinheiro et al., 2022). Here, KNG1 is linked to angioedema.