NCL caused by progranulin deficiency, CLN11, was first described in 2012 in two siblings carrying homozygous GRN mutations (c.813_816del; p.Thr272Serfs*10) resulting in no detectable progranulin in blood or peripheral tissues [58]. The gene discussed is GRN; the disease is hyperinsulinemic hypoglycemia, familial, 4.