Population frequency of HLA haplotypes contributes to the prevalence difference of multiple sclerosis in Ireland

Abstract

Although the numbers tested in this study were small the results suggest one of the factors accounting for the difference in MS prevalence across the island of Ireland is likely to be variation in the genetic predisposition to MS within the Irish population.

Distribution Analysis of HLA-DRB1*1501, -DQA1*0102, -DQB1*0602, -DRB5*01, -A*0301 Alleles and Haplotypes in Normal Population of Khuzestan Province

“…The putative extended DRB1*1501 + -DQB1*0602 + -DQA-1*0102 + -DRB5*01 -haplotype frequency was 3% in Italian population [16] and in our population was 16.21%. Furthermore, the Irish normal cohort also showed a significantly higher carriage rate (55%) of the HLA-DRB1*1501 + -DQB1*0602 + relative to the normal population of Khuzestan (28.33%) [19]. Population of Khuzestan may be described by greater various haplotype and specific LD patterns compared with others population.…”

“…The rigidity of this haplotype is the result of recent population history and may indicate selection events. Due to LD patterns differ among populations, the analysis of African Americans, who have substantially smaller blocks of disequilibrium, is an attractive strategy to identify recombination events that will assist in the identification of disease genes [12] + in population may increase susceptibility to some disease as it was shown in different populations [13,[16][17][18][19]. The Dw2 haplotype has been associated with some autoimmune disease in most ethnicity especially caucasoids [20].…”

Individual and Joint Action of Environmental Factors and Risk of MS

“…31,32 van der Mei et al Of interest, a recent study conducted in Australia found a latitudinal gradient in the incidence of first demyelinating events, with the incidence rate increasing by 9.55% per degree increase in latitude. 33 Although differences in allele frequencies of HLA-DRB1 alleles might explain some of the variance in the European MS prevalence, 34,35 it is probable that the latitudinal gradient also has an environmental component. This finding is demonstrated by the gradient in relatively ethnically homogeneous populations in Australia 36,37 and New Zealand.…”

Aetiology: Neighbourhood watch

“…A study of genetic risk factors for MS in Ireland, for example, showed that the percentage of individuals with the genetic variants that put them at risk of MS was substantially lower in one county than in another one nearby 14 . "The genetic contribution doesn't explain even half the risk, " cautions Bar-Or, so it may be possible to prevent the disease by targeting the environmental factors involved.…”