LabCE alpha thalassemias
In what order do normal and abnormal hemoglobins migrate in alkaline electrophoresis (from cathode to anode)? S with C, A, H, F, A2 A2, S with C, H, F, A C with A2, S, F, A, H C with A2, F, S, A, H
C with A2, S, F, A, H
Which hemoglobins can be decreased in alpha thalassemia? (choose all that apply) Hb A Hb A2 Hb F Hb H
Hb A, Hb A2, Hb F
Hemoglobin H bodies are tetramers of which globin chain? alpha beta delta gamma
beta
what is the RBC morphology of alpha thalassemia intermedia?
slight hypochromic microcytosis, with codocytes, schistocytes and basophilic stippling. reticulocytes are moderately increased
What happens to red blood cells that are producing hemoglobin H (4 beta chains) due to an alpha thalassemia disorder?
the hemoglobin H precipitate out, leading to the destruction of the red blood cell in the spleen, and a hemolytic anemia
what is hemoglobin H disease?
three of the four alpha gene loci are deleted
What is thalassemia minor?
two of the four alpha gene loci are deleted
The gene loci for the alpha globin chains are adjacent to the locus for which other globin chain? beta delta epsilon zeta
zeta the order of globin gene loci on chromosome 16 is zeta, alpha 2, alpha 1
Hemoglobin H is found in which ethnic group? American Blacks Mediterraneans Southeast Asians Any ethnic group
Any ethnic group
What are hemoglobin H bodies, and how can they be seen / what do they resemble?
Hemoglobin H readily precipitates out and becomes an inclusion similar to basophilic stippling. it can be stained with brilliant cresyl blue, and resembles a golf ball
Which two of the following conditions can lead to a thalassemia? an amino acid substitution a deletion of a chromosome a deletion of a gene loci an inactivation of a gene
a deletion of a gene loci an inactivation of a gene
what is alpha thalassemia, or hydrops fetalis?
all four of the alpha gene loci are deleted
Nucleated red blood cells (NRBCs) are most often seen in which variant of alpha thalassemia? Alpha thalassemia major Alpha thalassemia intermedia Alpha thalassemia minor Silent carrier
alpha thalassemia major
Which disorder is characterized by a genetic code that is incompatible with life? heterozygous alpha thalassemia minor homozygous alpha thalassemia minor hemoglobin H disease alpha thalassemia major
alpha thalassemia major
What RBC morphology on a wright stained smear may indicate the presence of an unstable hemoglobin? Acanthocytes Codocytes Schistocytes Xerocytes
Schistocytes
Alpha thalassemia is defined as: The production of an abnormal form of hemoglobin due to the substitution of an amino acid in the alpha chain The decrease in the rate of production of Hb A due to a substitution of an amino acid in the alpha chain The decrease in the rate of production of alpha chains due to a partial or total deletion of the alpha genes
The decrease in the rate of production of alpha chains due to a partial or total deletion of the alpha genes
Match the alpha thalassemia variants below with their genotypic notation: (-a/aa) (-a/-a) (--/aa) (--/-a) (--/--)
(-a/aa) Silent carrier (-a/-a) homozygous thalassemia minor (--/aa) heterozygous thalassemia minor (--/-a) alpha thalassemia intermedia / hemoglobin H disease (--/--) Thalassemia Major / Hydrops fetalis
Mark all genotypes that cause alpha thalassemia minor -a/aa -a/-a --/aa --/-a --/--
-a/-a , --/aa
Which alpha thalassemia shows no anemia, although a slight decrease in the MCV and MCHC may be seen? Alpha thalassemia silent carrier Alpha thalassemia minor Alpha thalassemia intermedia (Hemoglobin H disease) Alpha thalassemia major (Hydrops fetalis)
Alpha thalassemia silent carrier
Newborns who will develop hemoglobin H disease may demonstrate up to 30% of which type of hemoglobin? Bart's Fetal Lepore Sickle
Bart's
Which set of chemistry results would most likely occur during hemolytic crisis in alpha thalassemia intermedia? Decreased lactate dehydrogenase (LD) and bilirubin, and increased haptoglobin Increased LD and bilirubin, and decreased haptoglobin Increased LD and bilirubin, and normal haptoglobin Normal LD and bilirubin, and decreased haptoglobin
Increased LD and bilirubin and normal haptoglobin. haptoglobin usually remains normal due to the absence of alpha chains in the destroyed cells
The bone marrow in alpha thalassemia usually demonstrates: aplasia hypoplasia normoplasia hyperplasia
hyperplasia the bone marrow in alpha thalassemia often demonstrates erythroid hyperplasia, as it tries to compensate for the anemia that is present
what is hemoglobin H?
in alpha thalassemia disorders, adults who would normally produce hemoglobin A (2 alpha 2 beta), the excess beta chains will combine to form hemoglobin H (4 beta)
what is hemoglobin bart's?
in alpha thalassemia disorders, infants producing hemoglobin F (2 alpha 2 gamma) the excess gamma chains will combine to form hemoglobin bart's (4 gamma)
What causes persons with alpha thalassemia intermedia to have jaundice?
increased bilirubin levels as a result of hemoglobin degradation from ongoing hemolysis
Which of the following laboratory test results is not usually increased in alpha thalassemia? iron binding capacity percent iron saturation lactate dehydrogenase bilirubin
iron binding capacity the iron binding capacity is normal or even decreased in alpha thalassemia because iron may remain in excess as inadequate amounts of hemoglobin are being formed
what is silent carrier?
one of the four alpha gene loci are deleted