HEMA LEC - Alpha Thalassemias Flashcards
Indicates division between genes inherited from both parents
/
the total complement of a genes in an individual is
4
Indicates a gene deletion
-
(one gene deletion)

a+ Thalassemia
3 functional working genes
Called a thal 2.
a+ Thalassemia
two gene deletion in the same chromosome
a0 Thalassemia
2 functional working genes. - Called a thal 1
a0 Thalassemia
denotes nonfunctioning (mutated gene, not deletion) gene:
Superscript T
defects in alpha globin affecting the formation of both fetal and adult hemoglobins
alpha thalassemia
can manifest in utero because alpha chain is a component of both fetal and adult Hb
alpha thalassemia
more stable
do not precipitate but instead form Hb tetramers called Hb Bart
gamma chains
gamma chains more stable
do not precipitate but instead form Hb tetramers called ______
Hb Bart
Is usually caused by deletion of 1 or more of the 4 α globin genes on chromosome 16
α Thalassemia
physiologically useless Hb (have
very high affinity to oxygen)
Hb Bart and Hb H
massive edema
(hydrops fetalis)
_____ accumulation and deposition are more toxic than __ chain accumulation and deposition.
Alpha chain
which is more severe: alpha or beta thalassemia
beta thalassemia
clinical syndromes
-α/αα
silent carrier α thalassemia
treatment for silent carrier α thalassemia
none
detection of silent carrier α thalassemia
DNA studies
hgb and hct of silent carrier α thalassemia
normal
Caused by two missing alpha genes. May be homozygous (-α/-α) or heterozygous (–/αα).
Alpha Thalassemia Minor.
• Exhibits mild microcytic, hypochromic anemia.
Alpha Thalassemia Minor.
•     May be confused with iron deficiency anemia.
Alpha Thalassemia Minor.
• Although some Bart’s hemoglobin (g4) present at birth, but no Bart’s hemoglobin present in adults
Alpha Thalassemia Minor.
2nd most severe form of alpha thalassemia
Hb H disease
usually caused by presence of only one intact alpha gene producing alpha chains
Hb H disease
results in accumulation of excess unpaired gamma or beta chains
born with 10-40% Bart’s Hb. Gradually replaced with Hb H
In adult, have about 5-40% Hb H
Hb H disease
live normal life; however, infections, pregnancy, exposure to oxidative drugs may trigger hemolytic crisis.

Hb H disease
RBCs: microcytic/hypochromic with marked poikilocytosis
Numerous target cells
Hb H disease
In Hgb electrophoresis, fast moving band is correspondent to
Hb H
What Hb is vulnerable to oxidation
Hb H
Gradually precipitate in vivo to form Heinz-like bodies of denatured Hgb
Hb H
cells has been described as having golf ball appearance, esp. when stained with brilliant cresyl blue
Hb H disease
Hb H prep same as Retic prep but with extended time of incubation, instead of 15 min it will be
2 hrs
Most severe form.
Bart’s Hydrops Fetalis Syndrome
Incompatible with life.
Bart’s Hydrops Fetalis Syndrome
Have no functioning α chain genes (- -/- -).
Bart’s Hydrops Fetalis Syndrome
edema and ascites caused by accumulation serous fluid in fetal tissues as result of severe anemia
hydrops fetalis
Also we will see hepatosplenomegaly and cardiomegaly.
Bart’s Hydrops Fetalis Syndrome
Types of Hb in Bart’s Hydrops Fetalis Syndrome [3]
Hb Bart, along with Hb Portland and traces of HbH.
The blood film of neonate with hemoglobin Bart’s hydrops fetalis shows [3]
anisocytosis, poikilocytosis and numerous nucleated red blood cells (NRBC).
Only and only the presence of few
the peripheral blood of the ____ is considered normal.
newborn
Micro / Hypo
Mild Anemia
Bart’s 2-8% (at birth)
Hb H
Hetero a° a-thal-1 OR Homo a+ a-thal-1
Moderate Micro/Hypo anemia: Barts
a+ + a° Hb-H
Disease
Hb A 0%, Bart’s 70-80% Portland 10-20%
homo a° Hydrops
different types of Hgb contain different ____ which determine the electrophoretic mobility and gives specific bands on electophoretic papers when hemolystae is undergone electrophoresis
surface charge
Hgb that can be measured by EF
A, A2, Bart, C, D, E, F, H, S
