Biochem Lab Quiz 4

What type of HgB is made of 2 alpha chains and 2 gamma chains?

HbF (fetal)

What is the percentage of HbF (fetal)?

0.5-2

What HgB is made up of 2 alpha chains and 2 beta chains?

HbA (adult)

What is the percentage of HbA (adult)?

90%

What is the main hemoglobin type that is affected by beta thalassemia?

HbA

What HgB is made up of 2 alpha chains and 2 delta chains?

HbA2 (adult)

What is the percentage of HbA2?

<5%

What is the cause of beta thalassemia?

autosomal recessive mutation on chromosome 11

defect in protein transcript

Beta thalassemia causes what?

reduction or absence of beta globin (HgA)

Beta thalassemia is most common where

mediterranean, Africa, south east asia

B thalassemia minor is caused by what type?

1 normal parent gene and 1 reduced or absent gene

Chance of getting B thalassemia minor if both parents are carriers?

50%

B thalassemia intermedia is caused by what type?

1 reduced gene and another reduced gene

Chance of getting B thalassemia intermedia if both parents are carriers?

25%

Chance of getting B thalassemia major if both parents are carriers?

25%

B thalassemia major is caused by what type?

1 absent gene and another absent gene

Treatment of B thalassemia include what?

blood transfusions

iron chelating agents

splenectomy

stem cell → bone marrow transplant

In labs what type of RBCs do you find?

hypochromic and microcytic

In b thalassemia what hemoglobin type is reduced, almost to none?

HbA

In b thalassemia what hemoglobin type overcompensates?

HbF

“Hair on end of skull” is due to what in beta thalassemia?

RBC produced by flat bones of skull

Erythropoeisis occurs mainly where?

bone marrow

What stimulates Erythropoeisis to begin?

EPO

First few steps of erythropoeisis occur where?

bone marrow

How does an RBC start off and then develop?

Starts off with organelles and loses them as it develops, including nucleus

What is the RBC called when we start developing hemoglobin?

erythroblast

RBC starts off as what? Develops into what?

Proerythroblast → erythroblast → reticulocyte → erythrocyte

Lead toxicity inhibits what enzymes?

ALA dehydrogenase

Heme synthase

Autosomal recessive gene can’t happen on what?

sex chromosomes

it CAN affect other chromosomes

Abnormal erythoblast from beta thalassemia causes what?

Heinz bodies and target cells

What does spleen do during b thalessemia?

try to destroy abnormal blood cells in circulation → leads to anemia

What occurs as body tries to create more RBCs in b thalessemia?

liver, spleen and bone marrow try leading to → hepatosplenomegaly and skeletal deformities

Increasing erythroferrone in a patient w/ b-thalassemia does what?

decrease hepcidin → increased iron absorption in intestine → iron overload

Marfan Syndrome is what type of disease?

Autosomal dominant inheritance on chromosome 15

Chances of getting Marfan’s syndrome

50%

FBN1 mutation in Marfan’s causes what defect?

defective fibrillin-1

defective fibrillin-1 causes what?

weak scaffolding for elastin + loss of TGF beta control (increase TGF B)

Increase in TGF-B causes what?

abnormal cell proliferation, differentiation, healing

increased fibrosis

How is the expression of marfan’s?

variable

What is the percentage of gaining Marfan’s from new mutation?

25%

Defective elastic fibers are what?

weak and have fragmentation

Marfan’s will result in what kind of bone growth and what kind of connective tissue?

excessive bone growth and weak connective tissue/loose joints

What happens to aortic wall in Marfan’s syndrome?

weakness in wall → aneurysm (ballooning)

Ectopia lentis means what?

lens dislocation/subluxation

Mitral valve prolapse means what?

billowing leaflets - > regurgitation

Marfanoid habitus means what?

tall, thin body with long extremities

Arachnodactyly means what?

spider fingers

Dolichocephaly means what?

long narrow head shape

Dolichostenomelia means what?

disproportionately long limbs

What are the major ghent criteria for Marfan’s syndrome?

Aortic dilation, ectopia lentis, FBN-1 mutation, family history

Do 2 major criteria plus multiple minor mean you have Marfan’s?

yes

Differential diagnosis for Marfan’s?

homocysturnia, MEN2B, Ehler’s-Danlos

Ehler’s-Danlos symptoms?

fragile skin, NO aortic dilation

Leading cause of death in cardiac complications of Marfan’s is what?

aortic aneurysm/dissection

Complementary management of Marfan’s is what?

low carb diet → decrease in insulin resistance, vessel protection!

supplement: Mg, Vit C, CoQ10

Stress reduction

Gentle chiropractic care for posture/scoliosis

Conventional management of Marfan’s is what?

Avoid strenuous sports

Echo, eye, ortho surveillance

Aortic root replacement if >5cm

BBs or ARBs(lower blood pressure)→ decrease wall stress, block TGF-B