To investigate the impact of −129C > T polymorphism on AHR transcript level and the correlation between SP1 and AHR expressions, we measured the AHR and SP1 mRNA levels in the peripheral blood mononuclear cells (PBMCs) from 23 vitiligo patients and 23 age- and sex-matched controls harboring different AHR −129 genotypes (n = 16 for CC, n = 6 for CT and n = 1 for TT in vitiligo patients; n = 17 for CC, n = 5 for CT and n = 1 for TT in controls; Hardy–Weinberg equilibrium test: χ2 = 0.571, P = 0.450). The gene discussed is SP1; the disease is vitiligo.