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🌱 來自: Thalassemias

Take of message of Thalassemias

• The thalassemias are characterized by a reduced rate of synthesis of one of the globin subunits of the hemoglobin molecule.
• The intracellular precipitation of the excess, unpaired globin chains in thalassemia damages red cell precursors and circulating red cells, resulting in ineffective erythro- poiesis and hemolysis.
• The α-thalassemias are primarily due to DNA deletions. Four α-genes are normally present, so multiple pheno- types are possible when gene deletions occur.
• The β-thalassemias are caused by >200 different mutations, usually point mutations, with a wide variety of genetic abnormalities documented.
• α-thalassemia trait is characterized by mild asymptomatic anemia with microcytic indices and a normal hemoglobin electrophoresis.
• The hemoglobin electrophoresis in β-thalassemia trait reveals increased levels of hemoglobin A2 and variably increased hemoglobin F.
• Thalassemia can be clinically classified into transfusion- dependent thalassemia (TDT) or non-transfusion- dependent thalassemia (NTDT).
• Patients with TDT require regular blood transfusions for survival, while those with NTDT who have a mild to moderate phenotype require intermittent transfusions during periods of acute illness, infection, or pregnancy, or to allow for normal growth and development.
• Iron overload is a complication of TDT and NTDT, and monitoring of iron load with serum ferritin, and liver and cardiac iron content by MRI are important to optimize chelation therapy initiation and management.
• Hemolytic anemia, ineffective erythropoiesis, and iron overload contribute to multiple complications of TDT and NTDT including bone deformities, cardiac failure, arrhythmia, liver cirrhosis, HCV infection, thrombosis, endocrinopathies, osteoporosis, leg ulcers, and pulmonary hypertension.
• Partner testing and genetic counseling in individuals with α-thalassemia trait is important so that a pregnant woman with a risk of a homozygous α0-thalassemia fetus can consider further testing, early termination, or undergo intrauterine transfusions to support fetal growth should they wish to maintain the pregnancy.