Diagnostic micrographs of the patient’s bone marrow biopsy specimen and aspirates and genetic mutation. (A) Wright-Giemsa–stained low-power view of diagnostic patient bone marrow biopsy specimen before initiation of G-CSF administration showing hypercellularity with left-shifted myeloid maturation. Original magnification ×400. (B) Wright-Giemsa stained high-power view of bone marrow aspirate demonstrating vacuolization of myeloid precursors and pyknotic nuclei (2% myeloblasts, 12% promyelocytes, 26% myelocytes, 26% metamyelocytes, 8% bands, 9% segmented neutrophils). Original magnification ×1000. (C) High-power view of bone marrow aspirate after chronic G-CSF administration showing improved myeloid maturation (2% promyelocytes, 10% myelocytes, 11% metamyelocytes, 20% bands, 36% segmented neutrophils). Original magnification ×600. (D) Biallelic patient gene mutation showing compound heterozygous mutations in the G6PC3 gene. The paternal mutation at the terminus of exon 2 is a novel pathogenic variant that has not been described previously.