C1QTNF5 encodes a member of a family of proteins that function as components of basement membranes and may play a role in cell adhesion. Mutations in C1QTNF5 have been associated with late-onset retinal degeneration. The protein may be encoded by either a bicistronic transcript including sequence from the upstream membrane frizzled-related protein gene (MFRP), or by a monocistronic transcript expressed from an internal promoter.