This gene encodes a member of the histidine acid phosphatase family of proteins. Despite containing a histidine acid phosphatase domain, the encoded protein functions as an inositol pyrophosphate kinase, and is thought to lack phosphatase activity. This kinase activity is the mechanism by which the encoded protein synthesizes high-energy inositol pyrophosphates, which act as signaling molecules that regulate cellular homeostasis and other processes. This gene may be associated with autism spectrum disorder in human patients. [provided by RefSeq, Sep 2016].