Linkage and association of HLA class II genes with vitiligo in a Dutch population

Background Serological typing of HLA has shown discrepancies in HLA associa tions with vitiligo in different ethnic populations. Objectives To perform genotyping of HLA class II genes on a Dutch vitiligo population in order clearly to identify susceptible and protective HLA alle les in vitiligo. Methods HLA typing was carried out by amplifying genomic DNA by polymerase chain reaction (PCR) followed by dot-blot hybridization with sequence-speci fic oligonucleotides (SSO). Fifty Dutch vitiligo probands, and their parent s (150 individuals) and 204 healthy controls were studied. Results Family-based case-control association studies and linkage disequili brium analysis showed the linkage and association of DRB4*0101 allele with vitiligo (P-c = 0.0016, relative risk = 2.21). The family-based association study also provided evidence for linkage and association of DQB1*0303 alle le with vitiligo (chi (2) = 7.36, P = 0.006). We measured the clinical rele vance of the test by calculating the prevalence corrected positive predicti ve values (PcPPV). The PcPPV of disease for the DRB4*0101 allele was 0.017 and for the DRB4*0101/0101 genotype was 0.0358. In other words, a DRB4*0101 /0101 genotype carries a 3.58% risk of developing vitiligo. Conclusions Both DRB4*0101 and DQB1*0303 alleles provide significant suscep tibility for vitiligo.