Nogo Receptor Deficiency (NgR1; Rtn4r; 22q11.21; MIM 605566), (NgR2; Rtn4rl2; 11q12.1; MIM 610462), (NgR3; Rtn4rl1; 17p13.3; MIM 610461). Here, RTN4R is linked to hyperinsulinemic hypoglycemia, familial, 4.