An unusual DRB1*1503 haplotype without a detectable DRB5 locus in a black African family.

A DRB1*1503 allele not associated with DRB5 locus has been detected in an African family during routine HLA typing for bone marrow transplantation. PCR/SSOP analysis showed the DR2-associated alleles in all the family members but the DRB5 locus appeared to be absent in the patient and his brother. The samples were then analyzed for the presence of DRB6 pseudogenes and we found that the unusual haplotype was associated with DRB6*0101 allele. This finding strengthen the hypothesis of a recombination hot spot between DRB1 and DRB6 genes.