SBDS and neutropenia: Note that, although levels of Cebpa mRNA were significantly upregulated in the HSC population in neutropenia, they were substantially lower than in downstream progenitor subsets (TPM 5.10 ± 0.85 in HSC vs. 10.34 ± 1.16 in HPC1), and insufficient to drive recombination of the Sbds gene (see Fig. 1D–F).