While amyloid infiltration of articular structures is rare, the 'shoulder-pad' sign resulting from periarticular soft tissue amyloid deposition is essentially pathognomonic for immunogloblin (Ig) ( @entity1582 ) @entity2783 . We report the characterization of an amyloid protein (GRA) which produced @entity527 and the shoulder-pad sign. Amyloid fibrils were isolated from soft tissue shoulder mass of a @entity1 with @entity1582 . The fibrils were solubilized in @entity2097 HCl and proteins separated by Sepharose chromatography. @entity535 sequence of fractionated protein was determined after tryptic digestion. Sequence analysis of the major amyloid protein yielded a kappa III Ig light chain structure. The entire variable region (VL) plus the constant region (CL) to residue 207 was identified; but lesser amounts of CL than VL were present. A number of @entity535 residues previously not observed in kappa III VL proteins, plus a two @entity535 insert (95A, 95B), were identified. Kappa III VL amyloid proteins are rare and may show an increased predilection for soft tissue deposition. While several unique @entity535 residues that were identified in protein GRA may contribute to soft tissue amyloid deposition, no definite pattern is obvious from comparison with other reported kappa III amyloid proteins.

Shoulder-pad sign of XXXX : structure of an Ig kappa III protein.

@entity1 :: ('9606', 'Species') :: ['patient'] @entity527 :: ('MESH:D058225', 'Disease') :: ['articular amyloid deposits'] @entity2783 :: ('MESH:D000686', 'Disease') :: ['amyloidosis'] @entity535 :: ('CHEBI:33704', 'Chemical') :: ['amino acid', 'Amino acid'] @entity1582 :: ('MESH:D009101', 'Disease') :: ['systemic AL amyloidosis', 'AL'] @entity2097 :: ('MESH:D019791', 'Chemical') :: ['guanidine']
@entity2783 :: (MESH:D000686,Disease) :: ['amyloidosis']
