TIR-domain-containing adaptor protein gene TIRAP S180L polymorphism is not increased in Behçet's disease patients in two ethnic cohorts

The single nucleotide polymorphism (SNP) of TIRAP (Serine 180 leucine, S180L) that is shown to be associated with Behçet's disease (BD) in a European-derived cohort, but not in Middle Eastern patients is investigated in two other populations. Two cohorts of BD patients and controls from Turkey (n=797) and Italy (n=633) were genotyped by sequence specific primer-polymerase chain reaction (SSP-PCR) or TaqMan q-PCR assays. Genotype and allele frequencies in TIRAP S180L (rs8177374) were not different between BD patients and controls in either ethnicity. Furthermore, a meta-analysis between the Turkish and the Italian BD cohorts did not reveal an association between this non-synonymous SNP in TIRAP and BD (meta-analysis OR=0.94, meta-analysis p=0.61, Q statistic heterogeneity p=0.11). TIRAP S180L gene polymorphism, which was previously shown to be associated with BD in a Caucasian population, has been replicated in either Turkish or Italian population in our study.