In fibromyalgia syndrome cases, BDNF polymorphisms were associated with body mass index and anxiety score, specifically rs7124442 (A>G) (Fisher’s exact test χ2; p < 0.05; odds ratio (OR): 1.02) and rs2049046 (A>T) (Fisher’s exact test χ2; p < 0.05; OR: 0.55), respectively. The gene discussed is BDNF; the disease is Anxiety.