The pathophysiological importance of CASPR1/CNTN1 in MS has been attributed to the localization of these proteins in the myelin sheath at the paranodal region of the nodes of Ranvier present along myelinated axons (Coman et al, 2006) including the optic nerve (Stojic et al, 2018). The gene discussed is CNTNAP1; the disease is myeloid sarcoma.