CSF3R and hyperinsulinemic hypoglycemia, familial, 4: Incrosses of these fish generated null mutant F2 embryos of multiple compound csf3r mutant allelotypes, all of which showed obvious neutrophil deficiency upon inspection, with neutrophil population sizes being 30%, 36%, 38% and 45% of normal at 2, 3, 4 and 5 dpf, respectively (p < 0.05) (Fig. 2a–e).