FDXR and hyperinsulinemic hypoglycemia, familial, 4: Finally, most genetic disorders—not just those affecting steroidogenesis—are first identified in more severely affected individuals, with milder cases and “nonclassical” disease generally being reported later; thus the severely affected FDXR-deficient patients initially reported (111) probably do not represent a “typical picture” of FDXR deficiency; astute physicians should be alert for milder forms of this disorder.