HLA population genetics: a Lebanese population

Abstract

Human leukocyte antigen (HLA) typing was done in 426 Lebanese subjects of 88 families, in which 347 haplotypes were identified. The A, B, C, DRB1, DRB3/4/5, DQB1 and DPB1 loci were typed at high resolution. This study shows that information theory, as originally developed by Claude Shannon in 1948, provides a promising theoretical foundation to study the population genetics of a genetic system like HLA. Although Lebanese carry HLA alleles found in other populations, the association of these alleles into haplotypes is quite unique. Comparisons are made with the main ethnic groups. Two haplotypes well represented in the Lebanese population are not identified in any global population: L1 = {A*26:01:01 - B*35:01:01:01- C*04:01:01:01- DRB1*16:01:01 - DRB5*02:02 - DQB1*05:02:01} and L2 = {A*02:02 - B*41:01- C*17:01:01:01 -DRB1*11:04:01 - DRB3*02:02:01:01- DQB1*03:01:01:01}. By studying linkage disequilibrium in two blocks at a time, with the division of the blocks at different levels in consecutive cycles, conserved haplotypes in full linkage disequilibrium come to light, such as {A*26:01:01- B*35:01:01:01 - C*04:01:01:01 - DRB1*16:01:01 - DRB5*02:02 - DQB1*05:02:01- DPB1*03:01:01} and {A*33:01:01 - B*14:02:01 - C*08:02:01 - DRB1*01:02:01- DQB1*05:01:01:01 - DPB1*04:01:01:01}.