Laboratory testing was remarkable for neutropenia (260/μL, normal range (NR) 1800–6800/μL) possibly in the context of autoimmune antibodies (weak positive for CD16b) and lymphocytosis (86%, NR 20%–45%) with fluorescence-activated cell sorting (FACS) showing a decreased natural killer cell count (CD16 + CD56+: 0.04 × 109/L, NR 0.1–1.4 × 109). The gene discussed is FCGR3B; the disease is neutropenia.