Thalassemias

Question 1

define thalassemias

Answer 1

group of inherited disorders causing decreased rate of synthesis of a structurally normal globin chain

Question 2

are thalassemias quantitative or qualitative?

Answer 2

it is a decreased rate, so quantitative

Question 3

What characterizes the blood picture in thalassemias, in general?

Answer 3

microcytic, hypochromic with target cells

Question 4

How are thalassemias characterized?

Answer 4

by which globin chain is affected: alpha or beta chains

Question 5

What is the primary diff btw major and minor thalassemias?

Answer 5

Major causes severe anemia (or death in case of major alpha= hydrops fetalis); minor/trait causes milder anemias, some even not clinically symptomatic

Question 6

In what form of thalassemia would there be 100% hemoglobin F and why?

Answer 6

delta-beta, bc both are dereased so there is a compensatory increase in gamma (HbF predoms, A2 can’t be made. A2 is two alpha and two delta chains remember!)

Question 7

what is beta thalassemia major, and compare to minor

Answer 7

the absence of both beta genes on chromosome 11 means no globin chains will be produced (major); one gene defective means some normal beta chains will still be synthesized

Question 8

How is beta thalassemia major compensated? what is made instead of normal adult hemoglobin?

Answer 8

by production of HbF, up to 90%; the rest being Hbg A2 (alpha delta)

Question 9

Excess alpha chains in beta thalassemia major cause?

Answer 9

Heinz bodies form (precipitated hemoglobin chains) and cause rigidity, so the cells are removed by spleen or destroyed in the marrow