RS1 and X-linked retinoschisis: X‐linked retinoschisis (X‐linked juvenile retinoschisis; XLRS) is an early‐onset X‐linked inherited retinal disorder that leads to structural splitting of the neurosensory retina and severe visual impairment.[1] Retinoschisin‐1 (RS1) is a 224‐amino acid protein consisting of two conserved regions: an N‐terminal signal sequence (aa 1–23) and a discoidin domain (aa 64–219).