Imerslund-Grasbeck Syndrome

Imerslund-Grasbeck syndrome (IGS) is a rare condition characterized by vitamin B12 deficiency, often causing megaloblastic anemia. IGS usually appears in childhood. Other features may include failure to thrive, infections, and neurological damage. Mild proteinuria (with no signs of kidney disease) is present in about half of affected individuals. IGS is caused by mutations in either the CUBN or AMN gene and is inherited in an autosomal recessive manner. Treatment includes life-long vitamin B12 injections, with which affected individuals can stay healthy for decades.