RNF31 and hyperinsulinemic hypoglycemia, familial, 4: Biallelic LoF mutations in two of the LUBAC component: HOIL-1 (heme-oxidized IRP2 ubiquitin ligase 1; RBCK1) or HOIP (HOIL-1 interacting protein; RNF31), cause LUBAC deficiency, an autosomal recessive disease characterized by severe immunodeficiency, recurrent fever, and polyglucosan myopathy (73, 74).