GRN and hyperinsulinemic hypoglycemia, familial, 4: Since endogenous sPLA2-IIA expression in the B6 background is not sufficient to cause PGRN deficiency phenotypes, we performed an RNA-seq analysis with RNAs isolated from cortical regions of 5-month-old WT and Grn−/− mice in a B6 versus FVB/B6 mixed background to gain more insight into the mechanisms driving the phenotypic differences caused by PGRN loss in FVB and B6 backgrounds.