MCM4 and hyperinsulinemic hypoglycemia, familial, 4: Intriguingly, patients with overactive NFKB2, responsible for the so-called noncanonical NF-κB pathway, may develop ectodermal dysplasia, a feature typical for XLPDR (10), as well as adrenal insufficiency, which is a feature of the MCM4 deficiency phenotype (14–16).