Imerslund-Grasbeck syndrome: Difference between revisions
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'''Assistant Editor-in-Chief:''' Robert Shafton | [[CMG}}; | ||
'''Associate Editor-in-Chief''' [[User:Aditya Govindavarjhulla|Aditya Govindavarjhulla, M.B.B.S.]] [mailto:agovi@perfuse.org]; '''Assistant Editor-in-Chief:''' Robert Shafton | |||
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==Overview== | ==Overview== | ||
'''Imerslund-Grasbeck syndrome''' or Imerslund-Najman-Grasbeck syndrome or Imerslund-Grasbeck disease (IGS or INGS) is an autosomal recessive, familial form of vitamin B<sub>12</sub> deficiency caused by malfunction of the receptor located in the terminal ileum. | |||
==Signs and symptoms== | |||
Defined as those seen in any macrocytic, megaloblastic anemia: | |||
*[[Anemia]]: causing fatigue, conjuctival palor, pale complexion, and in some cases, a mild icterus (yellowing of the eye). | |||
*[[Glossitis]]("shiny tongue"): shiny, glossy tongue. | |||
*[[Cheilosis]](stomatitis): Inflammation of the edges of the lips and the oral mucosa. | |||
*[[Tabes dorsalis]] ("subacute combined degeneration of the spinal cord"): This involves the posterior section of the spinal cord and therefore involves [[proprioception]] (sense of position), touch, sense of vibration and in severe cases the [[lateral corticospinal tract]], causing spastic paralysis of the limbs. | |||
*Peripheral [[neuropathy]]: tingling sensation in the arms and legs. | |||
*[[Pancytopenia]]: decreased number of blood cells, due to decreased bone marrow production. | |||
*[[Methylmalonyl CoA-emia]]: defined as blood having and unusually high concentration of [[methylmalonyl CoA]]. | |||
*Peripheral findings such as [[hypersegmented neutrophils]] and large RBCs on high field view of the blood smears. | |||
*Laboratory findings indicating increased [[MCV]] (Mean Corpuscular Volume), decreased [[Hgb]]/[[Hct]] (indicating anemia), and decreased value of vitamin B<sub>12</sub> in the blood. | |||
*Proteinuria: protein found in the urine detected by analysis or by [[dipstick]]. | |||
*Reversal of all symptoms except neurological symptoms, by IV injection of vitamin B<sub>12</sub>. | |||
*[[Schilling test]] indicating <u>no</u> radioactive vitamin B<sub>12</sub> in the urine. (This test has dropped out of favor and should not be tried in patients with any form of renal failure). | |||
==Genetics== | |||
The disease is autosomal recessive, and can therefore skip generations. Mutations in either amnionless (AMN) or cubilin can be the culprit. The suspected chromosome is 14.<ref name=Grasbeck2006/> Due to its autosomal recessive pattern of inheritance, affected individuals (persons possessing a [[homozygous]] [[recessive]] [[genotype]]) need to undergo genetic counselling to identify risk of family members who might be [[heterozygous]] [[genetic carrier]]s. | |||
Revision as of 05:49, 8 July 2012
[[CMG}}; Associate Editor-in-Chief Aditya Govindavarjhulla, M.B.B.S. [1]; Assistant Editor-in-Chief: Robert Shafton
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Overview
Imerslund-Grasbeck syndrome or Imerslund-Najman-Grasbeck syndrome or Imerslund-Grasbeck disease (IGS or INGS) is an autosomal recessive, familial form of vitamin B12 deficiency caused by malfunction of the receptor located in the terminal ileum.
Signs and symptoms
Defined as those seen in any macrocytic, megaloblastic anemia:
- Anemia: causing fatigue, conjuctival palor, pale complexion, and in some cases, a mild icterus (yellowing of the eye).
- Glossitis("shiny tongue"): shiny, glossy tongue.
- Cheilosis(stomatitis): Inflammation of the edges of the lips and the oral mucosa.
- Tabes dorsalis ("subacute combined degeneration of the spinal cord"): This involves the posterior section of the spinal cord and therefore involves proprioception (sense of position), touch, sense of vibration and in severe cases the lateral corticospinal tract, causing spastic paralysis of the limbs.
- Peripheral neuropathy: tingling sensation in the arms and legs.
- Pancytopenia: decreased number of blood cells, due to decreased bone marrow production.
- Methylmalonyl CoA-emia: defined as blood having and unusually high concentration of methylmalonyl CoA.
- Peripheral findings such as hypersegmented neutrophils and large RBCs on high field view of the blood smears.
- Laboratory findings indicating increased MCV (Mean Corpuscular Volume), decreased Hgb/Hct (indicating anemia), and decreased value of vitamin B12 in the blood.
- Proteinuria: protein found in the urine detected by analysis or by dipstick.
- Reversal of all symptoms except neurological symptoms, by IV injection of vitamin B12.
- Schilling test indicating no radioactive vitamin B12 in the urine. (This test has dropped out of favor and should not be tried in patients with any form of renal failure).
Genetics
The disease is autosomal recessive, and can therefore skip generations. Mutations in either amnionless (AMN) or cubilin can be the culprit. The suspected chromosome is 14.[1] Due to its autosomal recessive pattern of inheritance, affected individuals (persons possessing a homozygous recessive genotype) need to undergo genetic counselling to identify risk of family members who might be heterozygous genetic carriers.