Two enzymes involved in the phospholipase C signalling system, namely the myo-inositol monophosphatase (IMPase) and the inositol polyphosphate 1-phosphatase (IPPase), have been postulated as targets for the therapeutic action of lithium in manic-depressive illness.
Future studies are therefore need to determine whether allelic variants of the INPP1 gene are associated with a favourable efficacy of lithium in manic-depressive illness.