The human T-cell receptor variable gene segment TCRBV6S1 has two null alleles.

The extent of polymorphism in TCRBV6S1 was examined by screening 203 individuals of diverse ethnic backgrounds by using SSCP. Three alleles were detected, including two that were described previously (TCRBV6S1*1 and *2P). The third allele (TCRBV6S1*3P), identified in these studies, is a pseudogene because, similar to allele *2P, it contains a substitution of a highly conserved cysteine residue near CDR3. Among a panel of 126 Caucasian donors, alleles *1, *2P, and *3P were observed to have frequencies of 0.72, 0.12, and 0.16, respectively. The extent of this survey suggests that it is unlikely for there to be additional common variants of TCRBV6S1. The approach used here enables rapid typing for polymorphism in a TCRBV gene that results in an allelically determined hole in the TCR repertoire.