Flashcards in thalassemia vignette Deck (19)
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hemoglobin genes
16p13.3
11p15.5
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globin synthesis during development
before birth
high alpha and gamma
low beta
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glob in synthesis after birth
alpha stays high
beta rises about 3 months
gamma goes down
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Qualitative hemoglobinopathies
• Hb S
• Hb C
• Hb E
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Quantitative hemoglobinopathies Thalassemias
α thalassemia
β thalassemia
γ thalassemia
Δthalassemia
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Hemoglobin S
Hemoglobin S
a) Homozygous SS disease "Sickle Cell Anemia"
b) S heterozygous: AS, sickle trait
c) Sickle Syndromes:
1) Hemoglobin SC hemoglobinopathy
2) SB° thalassemia
3) SB+ thalassemia
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Hemoglobin C
a) Homozygous CC hemoglobinopathy
b) Heterozygous C, e.g. AC, or C trait
c) C-Beta thalassemia
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Hemoglobin E
a) Homozygous EE
b) Heterozygous AE
c) Combination: E-Beta thalassemia
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Hemoglobinopathies
269 million carriers of hemoglobin disorders in the world:
-15% of Africans are S carriers
-7% of SE Asians are E carriers
-4-5% of SE Asians and Mediterranean population are beta thal carriers
-350,000 babies are born throughout the world each year with major hemoglobin disorders
Majority of the children die undiagnosed, untreated or under-treated
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SE Asia:
SE Asia: α, β thalassemia and E
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Africa –
Africa – S, C, α and β thalassemia
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West Pacific
West Pacific – α and β thalassemia and E
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East Mediterranean
– β thalassemia and S
Pa
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Thalassemia is a
disorder in which a reduced rate of one or more of the globin chain synthesis leads to imbalanced globin chain production, defective hemoglobin production and damage to the red cells and their precursors.
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αThalassemia types:
a) α thalassemia major
b) α thalassemia 3 gene deletion (Hgb H disease)
c) α thalassemia 2 gene deletion (α thalassemia trait)
d) α thalassemia 1 gene deletion – clinically insignificant
e) α thalassemia + Hgb Constant Spring
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β Thalassemias:
β Thalassemias:
a) β thalassemia major "Cooley's anemia"
b) β thalassemia intermediate c) β thalassemia trait
d) SB° thalassemia
e) SB+ thalassemia
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Y Thalassemia:
Y Thalassemia: Clinically significant only at birth and usually over by 6 months of life.
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δ Thalassemia:
δ Thalassemia: Not significant by itself but can be a problem if β-δ thalassemia.
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