Extended HLA/complement allele haplotypes: evidence for T/t-like complex in man.

TLDR

Extended haplotypes may be maintained by human analogs of murine t mutants, which suppress crossover and bias male transmission. The study mapped the chromosomal distribution of HLA and complement alleles in normal Caucasian families. Eight extended MHC haplotypes were overrepresented, with HLA‑A showing little variation; notably, the HLA‑B8/DR3/SCO1/GLO2 haplotype was transmitted from males to 83 % of offspring, indicating a human t‑mutant–like effect.

Abstract

The chromosomal distribution of alleles for HLA-A,-B,-C, and -DR and the serum complement protein alleles of factor B and C2 and C4 was studied in normal Caucasian families. Eight combinations of HLA-B, DR, BF, C2, C4A, and C4B markers were found to occur in haplotypes at frequencies significantly higher than expected. In these combinations, which were defined as extended major histocompatibility complex haplotypes, HLA-A showed limited variation. A possible mechanism for the maintenance of extended haplotypes are human analogs of murine t mutants which are characterized by crossover suppression and male transmission bias. One human 6p haplotype, HLA-B8, DR3, SCO1, GLO 2, was found to be transmitted from males to 83% of their offspring. The same haplotype with GLO 1 had no transmission bias. It is suggested that this GLO 2-marked chromosome is a human analog of a murine t mutant.