Background：

This gene is a member of the insulin-like growth factor binding protein (IGFBP) family and encodes a protein with an IGFBP domain and a thyroglobulin type-I domain. The protein forms a ternary complex with insulin-like growth factor acid-labile subunit (IGFALS) and either insulin-like growth factor (IGF) I or II. In this form; it circulates in the plasma; prolonging the half-life of IGFs and altering their interaction with cell surface receptors. Alternate transcriptional splice variants; encoding different isoforms; have been characterized.