TCF4 and psychiatric disorder: These included the MHC region; DRD2, the dopamine D2 receptor involved in mood and emotion; MEF2C, a gene that regulates synaptic function; TCF4, a regulator of prefrontal neuronal excitability and RBFOX1, a gene splicing regulator that has also been implicated in other psychiatric disorders (Okbay et al., 2016; Wray et al., 2018; Howard et al., 2019).