lecture 16 alpha thalassemia

Question 1

alpha thalassemia is most frequently encountered in —–populations and its due to —-

Answer 1

asian and african american/a deletion or mutation of in one or more of the four alpha globin chains (Each person has 4 copies of the same alpha globin gene)

Question 2

the —-genes affected, the — alpha globin produced.

Answer 2

more/less

Question 3

silent carrier state means —

Answer 3

1 affected gene (one alpha gene is deleted, no hematologic abnormalities are seen.)

Question 4

silent carriers have —-hemolobin levels and red blood cells indices but—/ iften these individuals are only identified after —.

Answer 4

normal / can pass on te affected gene to their offsprin/aving a kid with HbH disease or alpha thalassemia trait (2 out of 4)

Question 5

only way to dianose silent carrier condition is by —

Answer 5

DNA analysis or alpha/ beta ratio ( 0.8/1)

Question 6

alpha thalassemia trait

Answer 6

2 affected genes (if 2 genes are deleted either homozygous (α -/ α -) or heterozygous (- - / α α), the
condition is α -thalassemia trait.

Question 7

Patients who have alpha thalassemia trait have red blood cells that are ——/ te periperal blood smear is similar to tat observed in—-

Answer 7

microcytic, hypochromic, have cereased MCV and have a mild chronic anemia and but generally dont experince any other symptoms. / beta thalassemia trait

Question 8

Hemoglobin A2 levels are— and the electrophoretic patterin is—/As such the picture may resemble—-but ——-. so diagnosis of alpha thalassemia trait is usually done by—

Answer 8

both are normal/ IDA /this is an anemia that does not respond to iron supplements/exclusion of other causes of microcytic anemia.

Question 9

what other kind of testing is available for alpha thalassemia?

Answer 9

confirmatory testing by DNA analysis is available but it is not usually done. alpha beta ratio may also be done (0.6/1)

Question 10

Hemoglobin H disease

Answer 10

3 affected genes/If three alpha genes are deleted (- - /- α), the condition is known as Hemoglobin H disease.
Reduced synthesis of alpha-globin results in a relative excess of beta-globin chain production
as well as reduced total production of hemoglobin.

Question 11

The reduced total hemoglobin production
yields——– However, a relative excess of beta-globin
production yields

Answer 11

the classic microcytic anemia of thalassemia /hemoglobin tetramers composed entirely of beta-globin tetramers, known
as Hb H. (Since there’s not enough alpha to pair up with the beta chains (remember, hemoglobin needs 2 alpha + 2 beta), the extra unpaired beta chains do something odd…

They clump together in groups of 4 to form Hemoglobin H (HbH))

Question 12

look at p2 pic

Question 13

Hb H is an ——– hemoglobin which causes a —–anemia known as Hb H disease. This anemia can range ——- and can cause —–

Answer 13

unstable/ emolytic/from moderate to severe/splenomegaly (enlarged
spleen).

Question 14

in HbH disease, RBCs are

Answer 14

microcytic and hypochromic with target cells, polycromasia and basophilic stippling

Question 15

polycromasia is ———–/basopilic stippling is—

Answer 15

Polychromasia (or polychromatophilia) is when your blood has young red blood cells that show up as slightly bluish or grayish on a blood smear under the microscope. /Basophilic stippling is when red blood cells have tiny blue dots inside them when looked at under a microscope. These dots are clumps of RNA that didn’t get cleared out properly.

Question 16

in Hb H disease, when the blood smear is stained with brilliant cresyl
blue,——–/Crystal violet or new
methylene blue supravital stains will detect ——-. they appear as —–

Answer 16

(vital)–HbH is precipitated/ HbH inclusions (precipitated Hb H/precipitated β
globin chains)/ fine blue to green precipitates that are evenly
distributed all over the cell.

Question 17

most HbH patients survive to

Answer 17

adult life and only become transfusion dependent in their later years

Question 18

Hemoglobin electrophoresis at alkaline pH reveals a

Answer 18

fast moving band that is actually the
fastest band, next to the Hb A band.

Question 19

pae 3 pic

Question 20

ow much Hb each type of Hb is in the persons blood

Answer 20

 HbA - >50%
 HbF - Normal
 HbA2 - Approx. 1.5%
 HbH - Up to 40% (HbH is unstable so this may be an underestimation)

Question 21

Alpha Thalassemia Major

Answer 21

also called hydrops fetalis, (4 affected genes).

Answer 22

most severe form of alpha thalassemia. In this condition, no alpha globin is
produced, therefore, no Hb A Hb F or Hb A2 are produced. The RBCs contain only Bart’s
hemoglobin, a tetramer of γ chains. Fetuses affected by alpha thalassemia major, become
anemic early in pregnancy. As such, they are usually miscarried, stillborn, or die shortly after
birth.

Question 23

case studies