the other dqa1 alleles have no defined serotype. there are 5 groups, dqa1*02, *03, *04, *05, *06. dqa1 within these groups are either invariant or produce the same α-chain subunit. dqa1*02 and dqa1*06 contain only one allele. dqa1*03 has three alleles which each produce nearly identical α. for dqa1*05, the dqa1*0501 and dqa1*0505 produce identical α. other dqa1*05 exist that produce variant α, but these are rare.