 This gene also plays a pivotal role in the expression and synthesis of SHBG, an important glycoprotein made primarily in the liver, which in addition to lowering insulin-resistance also serves in reducing levels of free Estrogen as-well as prolonging the half-life of Testosterone.Function of HNF4A gene can be effectively examined by siRNA knockdown based on an independent validation.Mutations in the HNF4A gene are associated with a form of diabetes called maturity onset diabetes of the young (MODY).