On the other hand, Akap11, Sp4, Gria3, and Dagla do not have known associations to DD/ID and appear to be relatively “SCZ/BP-specific.” Grin2a shows genetic association with DD/ID, however there appears to be allelic segregation - schizophrenia is associated with protein-truncating LoF variants whereas DD/ID is associated with missense mutations including dominant-negative gain-of-function mutations [5, 20]. Here, SP4 is linked to schizophrenia.