The amount of a 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase delta-1 (human) when measured in cerebrospinal fluid. The trait is level of 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase delta-1 (human) in cerebrospinal fluid (OBA_2058033). Also known as: cerebrospinal fluid 1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase delta-1 (human) amount.