PLCB1 and Intellectual disability: Indeed, mutations in PLCB1, DNM1, ARHGEF9 and SYNJ1 cause EIEE, and mutations in MBOAT7 as well as 13 genes with PIP-binding domains (ARHGEF6, CASK, CC2D1A, CNKSR2, COL4A3BP, DLG3, EPB41L1, FGD1, IQSEC2, KIF1A, OPHN1, SYNGAP1, TRIO) cause mental retardation (Table S1).