SLC1A2 and autism: Moreover, 30% of GLT1+/− GLAST+/− (double heterogeneous) mice with 50% of GLT1 and GLAST expression levels (and 30% increased extracellular glutamate levels [99]) exhibit behavioral and neuroanatomical abnormalities often observed in autism, including abnormal social interaction, seizures, and an enlarged amygdala and hippocampus [100].