title: Scleroderma: possible significance of silent alleles at the C4B locus.
mesh_terms: D000361:Agammaglobulinemia; D000483:Alleles; D003181:Complement C4; D015935:Complement C4b; D006680:HLA Antigens; D006720:Homozygote; D006801:Humans; D007137:Immunoglobulin alpha-Chains / Q000235:genetics; D008285:Major Histocompatibility Complex; D012595:Scleroderma, Systemic / Q000235:genetics*
chemical_list: D003181:Complement C4; D006680:HLA Antigens; D007137:Immunoglobulin alpha-Chains; D015935:Complement C4b