megaloblastic anemia syndromic disease Imerslund-Grasbeck syndrome https://github.com/monarch-initiative/mondo/issues/6743 Gräsbeck-Imerslund disease defect of enterocyte intrinsic factor receptor juvenile megaloblastic Anaemia juvenile megaloblastic Anemia MEDGEN:1640347 familial megaloblastic anemia Imerslund-Grasbeck syndrome (IGS) or selective vitamin B12 (cobalamin) malabsorption with proteinuria is a rare autosomal recessive disorder characterized by vitamin B12 deficiency commonly resulting in megaloblastic anemia, which is responsive to parenteral vitamin B12 therapy and appears in childhood. Imerslund-Grasbeck syndrome ICD9:281.3 GARD:0007006 MONDO:0009853 enterocyte cobalamin malabsorption Imerslund-Gräsbeck syndrome UMLS:C4551825 selective cobalamin malabsorption with proteinuria icd11.foundation:375969525 SCTID:360495000 MESH:C538556 OMIMPS:261100 Orphanet:35858 familial megaloblastic anaemia hereditary anemia inborn disorder of cobalamin metabolism and transport obsolete nephropathy secondary to a storage or other metabolic disease