Figure 5. Schematic representation of RDH5 and all mutations thus far published. The membrane-embedded N-terminus consists of 18 amino acids and the ectodomain, present in the lumen of the smooth endoplasmic reticulum (SER), spans amino acids 19–288. A C-terminal membrane-spanning domain encompasses amino acids 289–310, and a small cytosolic tail of eight amino acids resides in the cytosol of retinal pigment epithelium (RPE) cells. Both missense and protein-truncating mutations are distributed across the entire protein. Mutations identified in this study are indicated in red.