MYOM2 and C1 inhibitor deficiency: Apart from a few diseases, in which specific etiological or pathogenic therapeutic options are known (e.g., anakinra for Schnitzler syndrome or C1 inhibitor concentrate for acquired C1 inhibitor deficiency), treatment of MGCS involves myeloma-targeting agents or immunosuppressive and immunomodulatory medications, depending on the type of the disorder associated with M protein.