Strategy for distinguishing a new DQB1 allele (DQB1*0611) from the closely related DQB1*0602 allele via sequence specific PCR or direct DNA sequencing

A novel DQ6 allele (DQB1*0611) was identified via direct DNA sequencing in an African-American donor for bone marrow transplantation. The allele was not suspected on the basis of a sequence specific PCR assay which instead indicated the presence of DQB1*0602. DQB1*0602 and DQB1*0611 differ in exon 2 only at codon 9 resulting in a tyrosine substitution for phenylalanine. A modification of current DQB1 sequence specific PCR assays was devised which allows distinction between the closely related DQB1*0602 and DQB1*0611 alleles. Preliminary allele frequency studies suggest that DQB1*0611 is rare both in a non-African American sample and in Americans of African descent carrying DR11, DQ6 haplotypes. The selection of various DQB1*0611 detection methods is discussed.