Gene: [10p121/MGA1] megaloblastic anemia 1 (enterocyte cobalamin malabsorption); Imerslund-Grasbeck syndrome; [IGS ]
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HET |
Megaloblastic anemia and neurologic disturbances are common symptoms of deficiency of the coenzyme vitamin B12 (cyanocobalamin). The cellular uptake of the vitamin and its modified forms depends on the binding to the carrier proteins, intrinsic factor (IF) produced in the stomach, and transcobalamin, present in the circulation and various tissue fluids. Hereditary forms of cobalamin deficiency are known to relate to qualitatively abnormal IF (GEM:11q1/GIF), to decreased synthesis of transcobalamin (GEM:22q1/TCN2), and to a defect of the intestinal epithelium leading to decreased uptake of IF-cobalamin and failure to absorb cobalamin (Imerslund-Grasbeck disease). Imerslund-Grasbeck disease has been shown by linkage studies to be caused by mutation in a gene designated MGA1, located on 10p between markers D10S548 and D10S466. The defect has been thought to be related to abnormal epithelial translocation of cobalamin, perhaps due to decreased receptor function or expression (see GEM:10p121/CUBN)." |
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REF |
PAT,LIN,LOC "Aminoff M &: AJHG, 57, 824-831, 1995 |
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KEY |
hem, git, vit |
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CLA |
unknown, basic |
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LOC |
10 p12.1 |
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MIM |
MIM: 261100 |
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SYN |
IGS |
