HSF4 belongs to the HSF family. HSF4 is a DNA-binding protein that specifically binds heat shock promoter elements (HSE). The isoform HSF4A represses transcription while the isoform HSF4B activates transcription. HSF4 is a homotrimer which exhibits constitutive DNA binding and forms trimers even in the absence of stress. It is expressed in heart, skeletal muscle, eye and brain, and at much lower levels in some other tissues. Mutation of HSF4 will cause lamellar cataract which is known as Marner type cataract (CAM). Lamellar cataract is an autosomal dominant common type of infantile cataract. Finger malformation is observed in some kindreds. Inheritance of these forms of cataract is autosomal dominant.