disease has basis in dysfunction of CUBN autosomal recessive disease Imerslund-Grasbeck syndrome Imerslund-Grasbeck syndrome type 1 An autosomal recessive disorder characterized by onset of megaloblastic anemia associated with decreased serum vitamin B12 (cobalamin, Cbl) in infancy or early childhood. Low molecular weight (LMW) proteinuria is frequently present, but sometimes occurs later and is usually mild or subclinical. Patients often present with vague symptoms, including failure to thrive, loss of appetite, fatigue, lethargy, and/or recurrent infections. Some patients may present later in childhood with neurologic abnormalities related to B12 deficiency, such as sensorimotor neuropathy and/or cognitive disturbances. MGA-1 MGA1 MONDO:0100156 Mga1 NCIT:C131677 OMIM:261100 enterocyte cobalamin malabsorption enterocyte intrinsic factor receptor, defect of http://orcid.org/0000-0001-5208-3432 megaloblastic Anemia type 1 megaloblastic anemia, 1 megaloblastic anemia, Finnish type pernicious anemia, juvenile, due to selective intestinal malabsorption of vitamin b12, with proteinuria