Thalassaemia: Difference between revisions
(Created page with "'''Thalassaemia''' is a group of diseases characterised by one or more defective globin genes, causing haemolytic anaemia. Like sickle cell anaemia it is more common in Africa and the Mediterranean, but also south-east Asia. == Pathophysiology == We distinguish alpha and beta thalassaemia, based on whether the alpha or beta globin genes are defective. Alpha globin chain production is controlled by two genes, so there are four alleles that can...") |
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'''Thalassaemia''' is a group of diseases characterised by one or more defective globin genes, causing [[haemolytic anaemia]]. Like [[Sickle cell disease|sickle cell anaemia]] it is more common in Africa and the Mediterranean, but also south-east Asia. | <section end="clinical biochemistry" />'''Thalassaemia''' is a group of diseases characterised by one or more defective globin genes, causing [[haemolytic anaemia]]. Like [[Sickle cell disease|sickle cell anaemia]] it is more common in Africa and the Mediterranean, but also south-east Asia.<section end="clinical biochemistry" /> | ||
== Pathophysiology == | == Pathophysiology == | ||
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Severity of the anaemia increases with increased number of affected genes, and ranges from asymptomatic to mild haemolytic anaemia to severe haemolytic anaemia. If all four alpha genes are deleted, the condition is incompatible with life (Hb Barts -> hydrops foetalis). | Severity of the anaemia increases with increased number of affected genes, and ranges from asymptomatic to mild haemolytic anaemia to severe haemolytic anaemia. If all four alpha genes are deleted, the condition is incompatible with life (Hb Barts -> hydrops foetalis). | ||
<section begin="clinical biochemistry" /> | |||
== Diagnosis and evaluation == | == Diagnosis and evaluation == | ||
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* [[Haemoglobin electrophoresis]] – to confirm diagnosis | * [[Haemoglobin electrophoresis]] – to confirm diagnosis | ||
* DNA analysis (PCR) – to confirm diagnosis | * DNA analysis (PCR) – to confirm diagnosis | ||
<section end="clinical biochemistry" /> | |||
== Treatment == | == Treatment == | ||
In mild thalassaemias, no treatment is necessary. In severe ones, lifelong regular [[Blood transfusion|blood transfusions]] are necessary. Treatment with [[Iron chelator|iron chelators]] is necessary to prevent iron overload. [[Haematopoietic stem cell transplantation]] could be curative in severe cases. | In mild thalassaemias, no treatment is necessary. In severe ones, lifelong regular [[Blood transfusion|blood transfusions]] are necessary. Treatment with [[Iron chelator|iron chelators]] is necessary to prevent iron overload. [[Haematopoietic stem cell transplantation]] could be curative in severe cases. | ||
[[Category:Haematology]] | [[Category:Haematology]] | ||
Revision as of 18:04, 3 April 2024
Thalassaemia is a group of diseases characterised by one or more defective globin genes, causing haemolytic anaemia. Like sickle cell anaemia it is more common in Africa and the Mediterranean, but also south-east Asia.
Pathophysiology
We distinguish alpha and beta thalassaemia, based on whether the alpha or beta globin genes are defective. Alpha globin chain production is controlled by two genes, so there are four alleles that can be defective. Beta globin chain production is controlled by only one gene so there are only two alleles that can be defective.
Clinical features
The clinical features of each type depend on how many alleles are defective. In alpha thalassaemia, one or more of the four genes for the alpha globin chain are deleted. In beta thalassaemia, one or both of the genes for the beta globin chain are defective.
Severity of the anaemia increases with increased number of affected genes, and ranges from asymptomatic to mild haemolytic anaemia to severe haemolytic anaemia. If all four alpha genes are deleted, the condition is incompatible with life (Hb Barts -> hydrops foetalis).
Diagnosis and evaluation
- Laboratory results
- Corresponding to haemolytic microcytic anaemia
- RDW normal or ↑
- Peripheral blood smear
- Target cells
- Teardrop cells
- Bone marrow biopsy
- Reactive hyperplasia
- Haemoglobin electrophoresis – to confirm diagnosis
- DNA analysis (PCR) – to confirm diagnosis
Treatment
In mild thalassaemias, no treatment is necessary. In severe ones, lifelong regular blood transfusions are necessary. Treatment with iron chelators is necessary to prevent iron overload. Haematopoietic stem cell transplantation could be curative in severe cases.