title: Association and linkage of leprosy phenotypes with HLA class II and tumour necrosis factor genes.
abstract: Previous analyses indicate major gene control of susceptibility to leprosy per se and the HLA class II region has been implicated in determining susceptibility and control of clinical phenotype. Segregation analysis using data from 76 Brazilian leprosy multi-case pedigrees (1166 individuals) supported a two locus model as the best fit: a recessive major gene and a recessive modifier gene(s) (single locus vs two locus model, P = 0.0007). Combined segregation and linkage analysis to the major locus, showed strong linkage to HLA class II (HLA-DQB1 P = 0.000002, HLA-DQA1 P = 0.000002, HLA-DRB1 P = 0.0000003) and tumour necrosis factor genes (TNF P = 0.00002, LTA P = 0.003). Extended transmission disequilibrium testing, using multiple affected family members, demonstrated that the common allele TNF*1 of the -308 promoter region polymorphism showed linkage and/or association with disease per se, at a high level of significance (P < 0.0001). Two locus transmission disequilibrium testing suggested susceptibility (TNF*1/LTA*2) and protective (TNF*2/LTA*2) haplotypes in the class iii region. Taken together the segregation and HLA analyses suggest the possibility of more than one susceptibility locus in the MHC.
authors.affiliation: Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Addenbrookes Hospital, Hills Road, Cambridge CB2 2XY, UK.genmas@leeds.ac.uk
authors.forename: M A
authors.initials: MA
authors.lastname: Shaw
authors.forename: I J
authors.initials: IJ
authors.lastname: Donaldson
authors.forename: A
authors.initials: A
authors.lastname: Collins
authors.forename: C S
authors.initials: CS
authors.lastname: Peacock
authors.forename: Z
authors.initials: Z
authors.lastname: Lins-Lainson
authors.forename: J J
authors.initials: JJ
authors.lastname: Shaw
authors.forename: F
authors.initials: F
authors.lastname: Ramos
authors.forename: F
authors.initials: F
authors.lastname: Silveira
authors.forename: J M
authors.initials: JM
authors.lastname: Blackwell
mesh_terms: D001938:Brazil / Q000453:epidemiology; D005802:Genes, MHC Class II; D008040:Genetic Linkage; D006801:Humans; D007918:Leprosy / Q000453:epidemiology / Q000235:genetics*; D010641:Phenotype; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
chemical_list: D014409:Tumor Necrosis Factor-alpha