Imerslund-Grasbeck syndrome, also known as selective intestinal malabsorption of vitamin B12, 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. Other manifestations include failure to thrive and grow, infections and neurological damage. Mild proteinuria (with no signs of kidney disease) is present in about half of the patients, and sometimes with anatomical anomalies in the urinary tract. The syndrome was first described in Finland and Norway where the prevalence is about 1:200,000.