Crystallin AB is a member of the small heat shock protein family and expressed in several tissues including brain, kidney cardiac and skeletal muscle. Crystallin AB functions as a molecular chaperone and in intracellular architecture. Crystallin AB has shown to have interactions with CRYAA, CRYGC, CRYBB2, CRYBA1 and HSPB8. Defects in crystalline AB have been linked to cause myopathy myofibrillar type 2, cataract posterior polar type 2, and myopathy myofibrillar fatal infantile hypertonic alpha-B crystallin-related (MFMFIH-CRYAB).