GLUD1 and brain disorder: This raises fundamental questions on the molecular basis underlying the region-specific function of GluD1 at excitatory or inhibitory synapses and the synaptic dysfunction associated with GluD1 mutations in brain disorders (Cooper et al., 2011, Fallin et al., 2005, Glessner et al., 2009, Guo et al., 2007, Treutlein et al., 2009).