MTHFR Flashcards
what does MTHFR play a role in?
folate and homocysteine metabolism by catabolizing the conversion of 5,10-methylenetetrathydrofolate to 5-methyltetrahydrofolate (the primary circulatory form of folate)
what does the milder MTHFR deficiency result in? RF for what?
mild to moderate elevation of plasma total homocysteine (emerging RF for CVD)
what is the code of the thermolabile form of the enzyme?
common sequence variant at bp 677 which encoded the thermolabile form of the enzyme
what is hydros fetalis?
alpha-thalassemia = incompatible with life
what is the role of methylenetetrahydrofolate reductase?
role in processing amino acids
chemical reaction involving forms of folate
required for the multistep process that converts amino acid homocysteine to methionine
what is the MC polymorphism related to the risk of neural tube defects? what is specifically changed?
MTHFR gene mutation
cytosine replaced with thymine at position 677
people with the thermolabile form of MTHFR defect have increased levels of what?
increased levels of homocysteine in their blood
molecular location of MTHFR gene?
chromosome 1: bp 11,845,786 to 11,866,159
located on the short (p) arm of chromosome 1 at position at 36.3
what MTHFR variant is the most noteworthy and what does it result in?
677C–>T variant has been particularly noteworthy since it has become recognized as the MC genetic cause of hyperhomocysteinemia
normal 677 allele? mutated? one mutation? two mutations? %age loss of fxn with one mutation, with two mutations?
normal = C677C mutated = C677T one mutation = C677T +/- two mutations = C677T +/+ with one mutation get 40% loss of fxn, with two mutations get 70% loss of fxn
normal 1298 allele? mutated? associated loss of fnx with one mutation vs with two?
normal = A1298A
mutated = A1298C
one mutation = 20% loss of fxn
two mutations = 40% loss of function
if one mutation of both C677T and A1298C what is the loss of fxn?
50%
if two mutations of C677T and one of A1298C what is the loss of fxn?
70%
if two mutations of both C677T and A1298C what is the loss of fxn?
80-100% (only 50 cases known worldwide)
%age of enzyme activity with 1298AC heterozygous and 677CC?
83%
