Mice deficient in either GN-, GCC-, or the cGMP-dependent protein kinase operating downstream of GCC (PRKG2), exhibit enhanced cell proliferation in the crypts and a reduction in the amount of cells of the secretory lineage (Li et al. 2007a; Steinbrecher et al. 2002; Wang et al. 2012b). This evidence concerns the gene GUCY2C and ganglioneuroma.