The clinical course was complicated by G-CSF-refractory neutropenia, recurrent sepsis, fulminant Aspergillus flavus sinusitis with craniofacial destruction, and HLH-like syndrome (hyperferritinemia 2,258 ng/mL, elevated sCD25 8,450 U/mL). The gene discussed is CSF3; the disease is isolated hyperferritinemia.