The identification of a new HLA-DPB1 allele (*1302) in one family and the detection of a recombination event between the DR and the DQ regions in another Caucasian T1DGC family.

The analysis of families collected by the T1DGC and typed at high resolution for the HLA class I and class II loci provided an opportunity for identifying new alleles and rare recombination events. In one American Caucasian family, a novel allele (HLA-DPB1*1302), detected as an unusual pattern of probe binding, was identified in the mother and in one child. Amplicons from both individuals were sequenced and a new variant of DPB1*1301 with an A->T mutation [TAC to TTC in codon 64, (amino acid 35); Y to F] was confirmed. In another American Caucasian family, one child inherited an unusual haplotype, DRB1*1501-DQA1*0102-DQB1*0609-DPA1*0103-DPB1*0601 resulting from a recombination between the DRB1 loci on the maternal chromosomes DRB1*1501-DQA1*0102-DQB1*0602-DPA1*0103-DPB1*0401 and DRB1*1302-DQA1*0102-DQB1*0609-DPA1*0103-DPB1*0601.