1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase delta-1 is a protein in humans that is encoded by PLCD1 gene. The production of the second messenger molecules diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3) is mediated by activated phosphatidylinositol-specific phospholipase C enzymes. Essential for trophoblast and placental development.