Microfibrillar-associated protein 4 （MFAP4） is a member of Fibrinogen protein family and contains 1 fibrinogen C-terminal domain. The MFAP4 protein has similarity to a bovine microfibril-associated protein. MFAP4 has binding specificities for both collagen and carbohydrate. MFAP4 is believed to be an extracellular matrix protein that is involved in cell adhesion or intercellular interactions. MFAP4 deletion was found in 30 of 31 Smith-Magenis syndrome （SMS） patients.
