Formation of amyloidogenic light chain CDR3. The most likely mechanism is reported. Sequences are compared with the closest VL and JL segments. (A) λ light chains; (B) κ light chains. R mutations, upper case letters; S mutations, lower case letters. Nontemplate coded nucleotides (N) are shown in bold; P nucleotides are in parentheses. *Nucleotides apparently removed at recombination.