defective globin switching
persistence of fetal hemoglobin
microcytosis
small cells
hydrops fetalis
fetal death due to complete lack of alpha hemoglobin genes
What is the embryonic hemoglobin?
HbG
The tense hemoglobin state is the ______ state, while the relaxed state is _______ and planar.
deoxygenated; oxygen-bound
Where are most structural hemoglobin variants found?
in the Beta-globin chain
hemoglobin H disease
severe anemia because only 1/4 alpha globin gene is functional
What is non-covalently linked in between the globins?
iron and a heme group
How many genetic variants of hemoglobin are known?
600
What is the fetal hemoglobin?
HbF (alpha 2 gamma 2)
How do you test for sickle cell?
1) DNA sequencing with PCR or electrophoresis 2) southern blot
Thalassemia minor
mild phenotype; doesn't req transfusions
In beta-thalassemia, defects are seen _____.
postnatally only
How are hemoglobin C and hemoglobin S different?
Same codon, different mutations, different phenotypes
HbKemsey has _____ O2 binding while hemoglobin Kansas has ______ O2 binding.
too tight; too weak
Which form of hemoglobin is the best oxygen carrier?
alpha-beta
Where is hemoglobin synthesized?
in the bone marrow
How many copies of the beta globin gene are there?
1
What is the major adult hemoglobin?
HbA
In HbKempsey, the O2 binding affinity is _____, so _____ O2 is delivered to the tissues, and to compensate, red blood cells are ________. This condition is called _______.
higher; less; overproduced; polycythemia
The 5'-3' ____ order of genes within each cluster coincides with the _____ order of their expression during development.
spatial; temporal
structural variants/qualitative hemoglobinopathies
mutations that alter the globin's properties without affecting its synthesis
Phenotypically, having 2 out of the 4 alpha globin genes results in _____.
mild anemia
How many oxygens does each globin bind?
one each; 4 per molecule
hypochromia
pale blood cells
What is hereditary persistence of fetal hemoglobin?
benign conditions that impair the perinatal switch from gamma to beta globin synthesis (high GbF in adults)
Beta-thalassemia is most often caused by _______.
point mutations in the beta-globin gene
Alpha-thalassemia is a ______ of alpha-globin and an excess of _____.
low or no amount; beta and gamma
thalassemia major
beta-zero; no beta proteins being produced
How many identical copies of the alpha globin gene are there on each chromosome?
2
