Four distinct L-type calcium channels have been identified: alpha-1S, alpha-1C, alpha-1D, and alpha-1F.Alpha-1F L-type calcium channel is expressed in a variety of tissues, including the retina. Mutations in alpha-1F have been associated to human disorders such as X-linked cone rod dystrophy (CORDX3) and incomplete X-linked congenital stationary night blindness type 2 (CSNB2). The alpha-1F subtype is also expressed in the immune system. It has been shown to regulate T cell receptor signalling and T cell homeostasis.