In the mUPD genetic subtype, although there were no significant correlations recorded against plasma OT and any PWS symptom, plasma AVP was significantly and positively correlated with five PWS symptoms including TBPS (Figure 7), hyperphagia, social relating difficulties and self-absorbed and depressive behaviours (r2 = 0.71, p= 0.015; r2 = 0.79, p= 0.011; r2 = 0.72, p= 0.013; r2 = 0.65, p= 0.029; r2 = 0.71, p= 0.047, respectively). The gene discussed is AVP; the disease is Prader-Willi syndrome.