Serum periostin levels were positively correlated with age (rs = 0.261, P = 0.003), age at asthma onset (rs = 0.283, P = 0.001), ACT score (rs = 0.24, P = 0.007), FeNO levels (rs = 0.319, P < 0.001), peripheral blood eosinophil counts (rs = 0.36, P < 0.001), and the Th2-high to Th2-low ratio (rs = 0.195, P = 0.029) (Table 2). The gene discussed is POSTN; the disease is asthma.