Alpha-thalassemia
| Alpha-thalassemia | |
|---|---|
| Other names | α-thalassemia |
| Specialty | Hematology |
| Symptoms | Anemia, jaundice, enlarged spleen[1] |
| Complications | Iron overload |
| Usual onset | Inherited - present in utero |
| Causes | Genetically determined deficiency in alpha globin production[2] |
| Diagnostic method | Blood smear, hemoglobin electrophoresis, DNA sequencing |
| Differential diagnosis | Beta thalassemia, iron deficiency anemia |
| Treatment | Blood transfusion, possible splenectomy, bone marrow transplant[1][3] |
Alpha-thalassemia (α-thalassemia, α-thalassaemia) is an inherited blood disorder and a form of thalassemia. Thalassemias are a group of inherited blood conditions which result in the impaired production of hemoglobin, the molecule that carries oxygen in the blood.[4] Symptoms depend on the extent to which hemoglobin is deficient, and include anemia, pallor, tiredness, enlargement of the spleen, iron overload, abnormal bone structure, jaundice, and gallstones. In severe cases death ensues, often in infancy, or death of the unborn fetus.[5][6]
The disease is characterised by reduced production of the alpha-globin component of hemoglobin, caused by inherited mutations affecting the genes HBA1 and HBA2.[7] This causes reduced levels of hemoglobin leading to anemia, while the accumulation of surplus beta-globin, the other structural component of hemoglobin, damages red blood cells and shortens their life.[5] Diagnosis is by checking the medical history of near relatives, microscopic examination of blood smear, ferritin test, hemoglobin electrophoresis, and DNA sequencing.[5]
As an inherited condition, alpha thalassemia cannot be prevented although genetic counselling of parents prior to conception can propose the use of donor sperm or eggs.[8] The principle form of management is blood transfusion every 3 to 4 weeks, which relieves the anemia but leads to iron overload and possible immune reaction. Medication includes folate supplementation, iron chelation, bisphosphonates, and removal of the spleen.[5] Alpha thalassemia can also be treated by bone marrow transplant from a well matched donor.[9]
Thalassemias were first identified in severely sick children in 1925,[10] with identification of alpha and beta subtypes in 1965.[11] Alpha thalassemia has its greatest prevalence in populations originating from Southeast Asia, Mediterranean countries, Africa, the Middle East, India, and Central Asia.[7] Having a mild form of alpha thalassemia has been demonstrated to protect against malaria and thus can be an advantage in malaria endemic areas.[12]
- ^ a b Origa, Raffaella; Moi, Paolo; Galanello, Renzo; Cao, Antonio (1 January 1993). "Alpha-Thalassemia". GeneReviews. PMID 20301608. Archived from the original on 4 September 2016. Retrieved 22 September 2016.update 2013
- ^ BRS Pathology (4th ed.). Lippincott Williams & Wilkins medical. December 2009. p. 162. ISBN 978-1-4511-1587-1.
- ^ "Complications and Treatment | Thalassemia | Blood Disorders | NCBDDD | CDC". www.cdc.gov. Archived from the original on 23 September 2016. Retrieved 22 September 2016.
- ^ Lanzkowsky's Manual Of Pediatric Hematology And Oncology 6th Edition ( 2016).
- ^ a b c d "Alpha Thalassemia". Johns Hopkins Medicine. 27 January 2025. Retrieved 27 January 2025.
- ^ "Alpha-thalassemia - Symptoms, diagnosis and treatment | BMJ Best Practice". bestpractice.bmj.com. Archived from the original on 12 May 2021. Retrieved 17 November 2019.
- ^ a b "Alpha thalassemia: MedlinePlus Genetics". medlineplus.gov. Retrieved 27 January 2025.
- ^ "Thalassaemia - Thalassaemia carriers". National Health Service. 17 October 2022. Retrieved 27 January 2025.
- ^ "Clinical commissioning policy: allogeneic haematopoietic stem cell transplantation (Allo-HSCT) for adult transfusion dependent thalassaemia". NHS England. 10 November 2023. Retrieved 18 January 2025.
- ^ Stuart H. Orkin; David G. Nathan; David Ginsburg; A. Thomas Look (2009). Nathan and Oski's Hematology of Infancy and Childhood, Volume 1. Elsevier Health Sciences. pp. 1054–1055. ISBN 978-1-4160-3430-8.
- ^ Harteveld, Cornelis L.; Higgs, Douglas R. (28 May 2010). "α-thalassaemia". Orphanet Journal of Rare Diseases. 5 (1): 13. doi:10.1186/1750-1172-5-13. ISSN 1750-1172. PMC 2887799. PMID 20507641.
- ^ Wambua S, Mwangi TW, Kortok M, Uyoga SM, Macharia AW, Mwacharo JK, Weatherall DJ, Snow RW, Marsh K, Williams TN (May 2006). "The effect of alpha+-thalassaemia on the incidence of malaria and other diseases in children living on the coast of Kenya". PLOS Medicine. 3 (5): e158. doi:10.1371/journal.pmed.0030158. PMC 1435778. PMID 16605300.