Thalassaemia alpha
The thalassaemia alpha is a Genetic disease in connection with an anomaly of the synthesis of the alpha part of the Hémoglobine. The chain alpha is under the control of four Allèle S. One distinguishes:
- the Hemoglobin Barts when the four alleles of hemoglobin alpha are absent or inactive,
- the Hémoglobine H when the three of the four alleles of hemoglobin alpha are absent or inactive,
- the feature thalassemic alpha when two alleles are transferred
- thalassaemia alpha more for only one transferred allele.
The fetal form is the most severe demonstration with the early appearance of a Anasarque: Ascite, épanchement pericardial, épanchement pleural, edema generalized, weakens microcytaire and Hydramnios. The newborn presents a splénomégalie with hepatomegaly, a extra-medullary érythropoïése, a hydrocéphalie, cardiac and urogenital malformations. The death occurs quickly. This form is due to the presence of Bart hemoglobin
The traditional form by hemoglobin H is a haemolytic anemia microcytaire with Ictère, hepatomegaly, splénomégalie and some times of the osseous anomalies of thalassaemia béta.
The carriers of the feature thalassemic alpha have a microcytosis, a hypochromy and an abnormal percentage of A2 hemoglobin and F.
The carriers of a thalassaemia alpha more do not present an anomaly to numeration formulates blood or of the minor anomalies.
The search for change of gene HBA1 and HBA2 is positive in 90% of the cases.
No treatment is available in the event of fetal Anasarque.
The carriers of hemoglobin H will be able to profit from globular transfusion of Culot in the event of severe anemia with visceral repercussion. A splenectomy will be sometimes necessary. The treatments containing iron and some antipaludéens will be to avoid at these individuals.
Sources
- Renzo Galanello, Antonio CAD, Alpha-Thalassemia In GeneTests: Medical Genetics Information Resource (database online). Copyright, University off Washington, Seattle. 1993-2005]