Lecture 16: sickle cell anemia

Question 1

Sickle cell anemia or sickle cell disease is a ——- disorder that occurs when the sickle(s) gene is inherited from——(the homozygous SS state). Heterozygous inheritance of the sickle gene —- is referred to as —-

Answer 1

Worldwide/both parents (the homozygous SS state)/ (AS)/ sickle trait

Question 2

This is a disease, which is prevalent in ——-and in——- It was thought that this disease is caused by malaria because—— But in fact, it is a disease——

Answer 2

This country and in all countries which used to have malaria infestation (Africa which is probably the place of origin of the gene, Greece, India and the Middle East) / caused by malaria/ it develops where malaria is present /whose occurrence is beneficial to persons who have malaria because it protects against malaria.

Question 3

So what causes sickle cell disease.

Answer 3

The beta gene is present and active but the gene is not a normal beta gene it’s a mutant gene and the mutation occurs at position 17

Question 4

The replacement —— at the 17th nucleotide of the gene for the beta chain of hemoglobin changes the codon —-(for ——which codes vfor —-

Answer 4

Of A by T GAG for glutamic acid to GTG for valine

Question 5

The loss of —-is central of the patho physiology of sickle cell
disease.

Answer 5

loss of RBC elasticity

Question 6

In sickle cell disease, low oxygen tension promotes red blood cell
sickling and repeated episodes of sickling ——. These cells fail to —– when normal oxygen tension is
restored. They remain permanently sickle and they are known as —-.

Answer 6

damage the cell membrane and decreases the cell’s elasticity/return to normal shape/irreversibely sickle cells (ISC)

Question 7

As a consequence, these rigid blood cells are unable to —- as they pass
through narrow capillaries, leading to ——- a well as —– and —-

Answer 7

deform/increased desturction in the spleen/vessel occlusion/ ischaemia

Question 8

Symptoms can be severeand include ———

Answer 8

fatigue, weakness, pallor and a number of symptoms associated with sickle cell crises that result from vessel
occlusions.

Question 9

cause of anemia in sickle cell disease

Answer 9

1)destruction of RBCs
2) intravscular hemolysis to a certain extent
3) sickle cells only live 10-20 days but normal 90-120 days
BM attemots to compensate by creating new red cells, it does not match the rate of destruction.