B12 and folate deficiency Flashcards
In what form is Iron toxic ?
Free form
Ferric Iron is in what kind of form?
Oxidized Fe3+
Ferrous Iron is in what kind of Form?
Reduced Fe2+
What is the role of Transferrin?
Carry the Ferric form of Iron in the blood
What is the role of Ferritin?
Stores the Ferrous form of iron
What is the role of Hemosiderin?
storage of iron in a disorganized manner
Looking at lab values the Mean Corpuscular Volume refers to what?
The size of the erythrocyte (Microcytic vs Macrocytic)
When looking at lab values the Hemocrit number tells you what?
determines the number of RBCs in the body
What does it mean when hemoglobin is low?
There will be a decrease in iron carrying capacity
Why is iron binding low with transferrin compared to the others?
Because when its bound to transferrin its exposed to oxygen which can cause oxidative damage
What two things faciliate iron uptake?
Vitamin C and Ascorbic Acid
What 4 things inhibit iron uptake?
1) phytates
2) antacids
3) phosphates
4) tannins
What transports iron from the lumen into the enterocyte?
DMT1
What transports iron from the enterocyte into the circulation?
Ferriportin
When there is a decrease in transferrin saturation what does that mean?
It means there is not enough iron in the blood so transferrin is not taking it up as readily so it just circulates and circulates
If you have an elevated sTFR what does it mean?
means there is an increase in receptors to try and bind to iron. So basically not enough iron is present
during an infection or cancer pathogens need iron for there growth so what blocks ferriportin from releasing iron into the system?
Hepcidin
A patient with Inherited hemochromatosis what kind of gene polymorphism does he/she have?
HFE polymorphism
what does HFE polymorphism do?
It upregulates DMT1 during iron transport, so you will have an increase of iron into the cells of the Liver and Cardiac tissue.
An accumulation of Hemosiderin due to the HFE polymorphism is bad because of what?
Because it will disrupt ferritin storage and destroy its structure.
What are 2 examples of acquired Iron Loading anemia?
Thalassemia and Sideroblastic anemia
During Iron Loading anemia what will you see happen to the RBCS
RBCs will breakdown so there is a increase of iron in the circulation
In Chronic Liver disease what happens?
No longer able to store or regulate iron
What is the role of both Folate and B12 metabolism?
DNA synthesis
Which Deficiency has neurological symptoms like ataxia?
B12 deficiency
What 2 things are needed to take up B12 ?
Intrinsic Factor and colabamine receptor
What is pernicious anemia? and why does it occur?
B12 Deficiciency because of the loss of Intrinsic factor
A patient with a methylmalonyl CoA mutase deficiency will result int he accumulation of what substrate?
Methyl malonic acid
Methionine synthase needs which Cofactor to function properly?
B12
In the presence of Methionine synthase what does it convert homocystene to? and What is the role of that pathway?
Homocystiene is converted to methionine which is needed for the methylation of DNA/RNA and proteins
What is the Ironbound form of protoporphin IX called?
Heme
What is ferrochelatases job in the bone marrow?
It looks for Iron in the bone marrow. Once it finds iron it puts it on protoporphin IX
What happens to protoporphin IX after it is formed?
Gets put on a globin protein to make hemoglobin
Lead Poisoning will inhibit what two things?
ALA dehydratase and ferrochalatase
Why is iron able to enter the cell when its in the presence of ascorbic acid?
Ascorbic acid maintains iron in an available state (reduced state) for transfer by the DMT 1 transport protein
What are two Amino acids that can chelate Iron in order to bind to the transferrin ?
Glutamate and Aspartate (remember you need acidic amino acids to chelate the iron)
Which clinical presentation is expected to result in the greatest loss of bodily iron stores?
Menstruation
What is the name of a blood test which provides similar information to Transferrin saturation %?
Total Iron Binding Capacity (TIBC) (Remember a high saturation % would be a low total iron biding capacity and vice versa)
