This allele contains a polymorphism in codon 154 that encodes an isoleucine. This codon is included in a peptide originally identified as a component of the minor histocompatibility antigen H4. It is carried by the 129/J, BALB/c, BDP, DBA, MOLF, PERA/CamEi, SPRET/Ei and CAST/Ei strains. (J:85846)