RS1 and X-linked retinoschisis: Nevertheless, considering the current state of knowledge on the pathological role of MAP kinase activation in neurodegeneration 77, 78, 79, 80, 81, 82, we speculate that increased MAP kinase signalling due to retinoschisin deficiency can induce or contribute to XLRS‐associated neurodegenerative processes in humans, and apoptotic photoreceptor degeneration in the XLRS mouse model 40.