PIK3CD and schizophrenia: Thus, in human brains and in lymphoblastoid B-cell lines (LCLs) of subjects with schizophrenia, an ErbB4 risk haplotype (AGG; rs7598440, rs839523, rs707284) was found to be associated with elevated ErbB4 CYT-1 transcription and consequently raised expression of PIK3CD (p110δ).