SchS is characterized by the association of urticarial rash, monoclonal gammopathy (overwhelmingly IgMκ), and a variable combination of constitutional symptoms (fever, fatigue, weight loss), bone pain, osteosclerosis, and/or elevated inflammatory markers (erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP)). This evidence concerns the gene CRP and monoclonal gammopathy.