Prototypical examples of these CDDENT are glucose-galactose malabsorption (caused by mutations in the Na+/glucose cotransporter gene, SGLT1) (Martín et al., 1996), congenital lactase deficiency (mutations in the lactase gene, LCT) (Kuokkanen et al., 2006), sucrase-isomaltase (SI) deficiency (caused by mutations in the SI gene) (Ritz et al., 2003), congenital chloride diarrhea (caused by mutations in the solute carrier family 26 member 3 gene, SLC26A3) (Wedenoja et al., 2011); several other CDDENT can also be included in this category (Canani and Terrin, 2011) (Table 1). The gene discussed is SI; the disease is congenital sucrase-isomaltase deficiency.