MFRP (membrane frizzled-related protein) is a type II transmembrane protein expressed primarily in the retinal pigment epithelium (RPE) and ciliary epithelium that plays a critical role in ocular development and retinal function 1. The protein contains a frizzled-type cysteine-rich domain (CRD) along with tandem Cubilin domain repeats, suggesting a role as a regulator of WNT signaling 2. Loss-of-function MFRP mutations cause nanophthalmos (extreme hyperopia characterized by shortened axial eye length) and early-onset retinal degeneration with primary rod photoreceptor loss 31. Affected individuals also develop serious ocular complications including angle-closure glaucoma (present in 79.1% of patients), retinitis pigmentosa, retinal pigment epithelial atrophy, cystic macular edema, and exudative retinal detachment 34. Clinically, MFRP mutations represent the second most common genetic cause of nanophthalmos (36.5% of cases) after PRSS56 4. Gene therapy studies using AAV-mediated delivery of wild-type Mfrp to the RPE successfully restored retinal function, normalized axial length, and prevented photoreceptor degeneration in mouse models 356, suggesting this approach is therapeutically viable for MFRP-related disease.