In comparison with DRB1*1155 allele, DRB1*1103 differs at position 220/221, 'GC' is changed to 'CT', or DRB1*1125 differs at position 210/211, 'AG' is substituted with 'GA'. This results in a single amino acid exchange depending on the closest related allele investigated, whether DRB*1103 codon 74 alanine (GCG) is changed to leucine (CTG) or DRB1*1125 codon 71 arginine (GAG) is replaced with glutamic acid.