has material basis in germline mutation in C1S classic complement early component deficiency complement component C1s deficiency https://www.malacards.org/card/complement_component_c1s_deficiency MEDGEN:462428 NANDO:2200779 UMLS:C3151078 MESH:C565170 GARD:0015707 MONDO:0013419 complement component C1s deficiency C1SD A rare defect resulting in C1 deficiency and impaired activation of the complement classical pathway. C1 deficiency generally leads to severe immune complex disease with features of systemic lupus erythematosus and glomerulonephritis. OMIM:613783 immunodeficiency due to a classical component pathway complement deficiency