Imerslund-Grasbeck Syndrome 1, also known as pernicious anemia, juvenile, due to selective intestinal malabsorption of vitamin b12, with proteinuria, is related to imerslund-grasbeck syndrome 2 and vitamin b12 deficiency. An important gene associated with Imerslund-Grasbeck Syndrome 1 is CUBN (Cubilin), and among its related pathways/superpathways are Plasma lipoprotein assembly, remodeling, and clearance and Cobalamin (Cbl, vitamin B12) transport and metabolism. Affiliated tissues include kidney and skin, and related phenotypes are proteinuria and megaloblastic anemia