This gene encodes the heavy chain subunit of the pre-alpha-trypsin inhibitor complex. This complex may stabilize the extracellular matrix through its ability to bind hyaluronic acid. Polymorphisms of this gene may be associated with increased risk for schizophrenia and major depressive disorder. This gene is present in an inter-alpha-trypsin inhibitor family gene cluster on chromosome 3. [provided by RefSeq, Jul 2015].