RESUMEN
BACKGROUND: This study aimed to evaluate whether VNTR variants in the Endothelial Nitric Oxide Synthase (eNOS) and the XRCC4 gene play any role in nicotine dependence (ND) and/or Schizophrenia+ND (Sch+ND) ethiopathogenesis. METHODS: Present study included 100 individuals with ND, 60 patients with Sch+ND, and 70 healthy controls. These variants were analyzed using PCR. RESULTS: The cases with ND had higher eNOS VNTR-BB genotype than the healthy control subjects (p = 0.001). eNOS-AA genotype was lower in cases with Sch+ND and ND groups compared to the controls (p = 0.001, p = 0.001, respectively). eNOS-B allele was found significantly more frequently in Sch+ND group compared to the controls (p = 0.001). eNOS-A allele was significantly lower in ND group than the controls (p = 0.001). XRCC4-ID genotype was more common in the ND group than the control group (p = 0.001) as heterozygosity disadvantage. XRCC4-DD genotype was more common in the Sch+ND group compared to the controls (p = 0.035). The frequency of XRCC4-I allele was lower in the Sch+ND group compared to the controls (p = 0.012). CONCLUSIONS: Our results showed that eNOS and XRCC4 VNTR variants might play a potential role in Sch+ND and/or ND pathophysiology (Tab. 2, Ref. 48).