Transcobalamin II 775G>C polymorphism and indices of vitamin B12 status in healthy older adults.

Brief report Transcobalamin II 775G C polymorphism and indices of vitamin B12 status in healthy older adults

A common polymorphism (775G>C) in the vitamin B12 transport protein, transcobalamin II (TCII), has been identified in which proline replaces arginine at codon 259. We determined the influence of TCII genotype on indices of B12 status, including total serum B12, the amount of B12 bound to TCII (holoTCII), methylmalonic acid, and homocysteine, in 128 healthy older adults (ages 40-88 years). Mean ...

Transcobalamin II G775C Polymorphism and Indices of Vitamin B12 Status in Healthy Older Adults Running Head: Transcobalamin II Genotype and B12 Status

Genetic and lifestyle factors related to the periconception vitamin B12 status and congenital heart defects: a Dutch case-control study.

Maternal hyperhomocysteinemia is associated with congenital heart defects (CHDs) in the offspring. A low periconception vitamin B12 status is determined by genetic and lifestyle factors and causes hyperhomocysteinemia. We investigated methionine synthase reductase (MTRR) and transcobalamin II (TC) genes and maternal intake and serum concentrations of vitamin B12 in association with CHD risk. Se...

Evidence for intestinal origin of transcobalamin II during vitamin B12 absorption.

The plasma binding of newly absorbed, radioactively labelled vitamin B12 was studied during a urinary excretion (Schilling) test. Vitamin B12, after being absorbed from the gut, enters blood attached to transcobalamin II, which seems to be derived from the ileal enterocyte. The absorbed B12 re-enters the blood stream after the transcobalamin II-B12 complex is cleared by the liver and it is then...

Circulating antibody to transcobalamin II causing retention of vitamin B12 in the blood.

A patient with recurrent pulmonary abscess, weight loss, and alcoholism was found to have extremely high serum vitamin B12 and unsaturated vitamin B12-binding capacity (UBBC) levels. While transcobalamin (TC) II was also increased, most of his UBBC was due to an abnormal binding protein which carried greater than 80% of the endogenous vitamin B12 and was not found in his saliva, granulocytes, o...