SNPs in the TNF-α gene promoter associated with Behcet's disease in Moroccan patients

Behçet's disease (BD) is a multisystemic inflammatory disease, mainly characterized by recurrent oral and genital ulcers (GUs), skin lesions and uveitis. Several genetic factors such as the TNF-α gene have been evaluated as contributors to the pathogenesis of BD. We aimed to evaluate the association between six TNF-α SNPs and susceptibility to BD, or the major clinical manifestations, in Moroccan patients. The six SNPs studied were: c.-1211C>T (rs1799964), c.-1043C>A (rs1800630), c.-1037C>T (rs1799724), c.-556G>A (rs1800750), c.-488G>A (rs1800629) and c.-418G>A (rs361525), known as -1031T>C, -863C>A, -857C>T, -376G>A, 308G>A and -238G>A, respectively.

SNPs were genotyped by direct sequencing in 120 unrelated Moroccan BD and 112 ethnically matched healthy controls. Allele and genotype distributions were compared between groups using chi-square or Fisher's exact tests.

The frequency of the -1211C allele was higher in (i) BD patients than in controls [P = 0.02, odds ratio (OR) = 1.68, 95% CI 1.10, 2.56] and in (ii) patients with GUs than in those without (P = 0.002, OR = 3.84, 95% CI 1.55, 9.49). The -418A frequency was lower in patients with uveitis (P = 0.0003, OR = 0.19, 95% CI 0.07, 0.5).

We report the first association between BD and TNF-α SNPs in Moroccan patients. We mainly observed that -1211C constitutes a susceptibility allele for both BD and GU, as previously reported for other populations. The -418A allele could be considered as a good prognostic factor for anterior uveitis, in Moroccan BD patients.