However, only one study found an increase in anxiety-like behavior (Chen et al., 2006) while most other studies did not find an anxiety-like phenotype on BDNF heterozygous mice (Montkowski and Holsboer, 1997; Macqueen et al., 2001; Chourbaji et al., 2004; Ibarguen-Vargas et al., 2009). The gene discussed is BDNF; the disease is Anxiety.