Secreted frizzled-related protein 4 (SFRP4) is a member of the SFRP family that contains a cysteine-rich domain homologous to the putative Wnt-binding site of Frizzled proteins. SFRPs act as soluble modulators of Wnt signaling. The expression of SFRP4 in ventricular myocardium correlates with apoptosis related gene expression.

SFRP4 is a hub gene in a Type 2 Diabetes-associated gene coexpression module in human islets, and reduces glucose-induced insulin secretion through decreased β-cell exocytosis. Expression and release of SFRP4 from islets is enhanced by interleukin-1β. SFRP4 is elevated in serum several years before clinical diagnosis of Type 2 Diabetes. Individuals who have above-average levels of SFRP4 in the blood are five times more likely to develop diabetes in the next few years than those with below-average levels.