Identification of three new DRB3*(DRB3*0106, DRB3*0107 and DRB3*02022) alleles

Three novel DRB3* alleles were identified using CANTYPE (R) reverse hybridi zation assay. The initial unusual hybridization patterns of DRB3-specific p olymerase chain reaction (PCR)-amplified DNA from each subject were confirm ed by cloning and sequencing analysis. DRB3*0106 allele is identical to DRB 3*0101 except for a single nucleotide substitution (CTG --> GTG) changing c odon 38 from Leu to Val. This polymorphism is commonly found in DRB3*03 all eles. Compared with DRB3*0202, DRB3*02022 contains a single silent nucleoti de substitution (AAT --> AAC, both encoding for Asn) at codon 77. This poly morphism is also present in DRB3*0204 allele. The new DRB3*0107 allele has a sequence unique to DRB3 alleles. From codon 5 to codon 36 the sequence is identical to that of DRB3*0101 allele. From codon 37 to codon 87 the seque nce of DRB1*0107 allele is identical to that of DRB3*0202. This sequence wo uld thus explain the CANTYPE (R) DRB3-specific unusual pattern of reactions . The new DRB3*0107 could have arisen from a gene conversion between DRB3*0 101 and DRB3*0202 alleles, but the DRB3*0106 and the DRB3*02022 may have be en generated by a point mutation event. The DRB3*0107 allele was identified in a Caucasoid individual. The ethnic origin of the subjects carrying the other two alleles are unknown. The three alleles presented here were only i dentified once, in a total population of 49,000.