Correlation of 5-HTT, BDNF and NPSR1 gene polymorphisms with anxiety and depression in asthmatic patients

Asthmatic patients are known to have a higher risk of anxiety and depression. In the present study, we aimed to explore the association of serotonin transporter (5-HTT), brain-derived neurotrophic factor (BDNF) and neuropeptide S receptor 1 (NPSR1) gene polymorphisms with anxiety and depression in asthmatic patients. This was a cross-sectional study conducted on 143 asthmatic patients and 175 healthy volunteers. Of the asthmatic patients, 49 suffered from anxiety and 12 exhibited signs of depression. Patients with a lower level of education were more prone to depression. Both anxiety and depression were associated with poor asthma control as evaluated by the Asthma Control Test (ACT) score. The association of single nucleotide polymorphisms of BDNF, NPSR1 and 5-HTT with anxiety and depression in asthamtic patients was evaluated. The distribution of 5-HTT gene polymorphisms in the healthy group, the group with asthma but without anxiety, and the group with asthma and anxiety had significant differences. Females with asthma and anxiety were more prone to BDNF polymorphism. Also, BDNF gene distribution exhibited significant differences among those in the healthy group, the group with asthma but no depression, and the group with asthma and depression; however, NPSR1 gene distribution did not vary greatly between the groups. The anxiety score was significantly affected by the interaction between 5-HTT (LL, S(+)) and BDNF (A(+), GG) (H=5.99, P=0.015). The depression score was significantly affected by the interaction between BDNF (A(+), GG) and NPSR1 (AA, T(+)). We noted that both anxiety and depression led to poor asthma control. The interaction between 5-HTT (LL) and BDNF (A(+)) increased the risk of anxiety, and the interaction between BDNF (A(+), GG) and NPSR1 (AA, T(+)) increased the risk of depression in asthmatic patients.