Deduced amino acid sequences of the VL regions of amyloidogenic light chains. Comparisons are made with the most homologous germline gene. (A) λ light chains; (B) κ light chains. R mutations, upper case letters; S mutations, lower case letters; R mutations in JL are shown in bold, S mutations are underlined. *Germline segment isolated from patient DNA. A continuous line indicates the amino acid sequence that was also found in the monoclonal proteins isolated from amyloid fibrils (DEP and CAR) and urine (PAP and SEM). Protein sequencing of the N-terminal portion of λ light chains showed the absence of the first amino acid in DEP and SEM and of 4 residues in PAP. The absence of the first residue occurs in many λIII light chain protein sequences,22 whereas multiple amino acids were missing in an amyloid λ light chain recently reported.23