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Flashcards in thalassemia vignette Deck (19)
1

hemoglobin genes

16p13.3

11p15.5

2

globin synthesis during development
before birth

high alpha and gamma

low beta

3

glob in synthesis after birth

alpha stays high

beta rises about 3 months
gamma goes down

4

Qualitative hemoglobinopathies

• Hb S
• Hb C
• Hb E

5

Quantitative hemoglobinopathies Thalassemias

α thalassemia
β thalassemia
γ thalassemia
Δthalassemia

6

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

7

Hemoglobin C

a) Homozygous CC hemoglobinopathy
b) Heterozygous C, e.g. AC, or C trait
c) C-Beta thalassemia

8

Hemoglobin E

a) Homozygous EE
b) Heterozygous AE
c) Combination: E-Beta thalassemia

9

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

10

SE Asia:

SE Asia: α, β thalassemia and E

11

Africa –

Africa – S, C, α and β thalassemia

12

West Pacific

West Pacific – α and β thalassemia and E

13

East Mediterranean

– β thalassemia and S
Pa

14

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.

15

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

16

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

17

Y Thalassemia:

Y Thalassemia: Clinically significant only at birth and usually over by 6 months of life.

18

δ Thalassemia:

δ Thalassemia: Not significant by itself but can be a problem if β-δ thalassemia.

19

B thalassemia clinical features

1. dense skull/marrow expansion
2. enlarged spleen
3. osteopenia/bone changes
4. iron overload
5. growth and endocrine features