The definition and epidemiology of non-transfusion-dependent thalassemia.

Inherited hemoglobin-related disorders, which include the structural variants (hemoglobin S, C, and E) and the alpha (α)- and beta (β)-thalassemias, affect more than 300,000 children annually, particularly in malaria-endemic regions stretching from sub-Saharan Africa and the Mediterranean to Southeast Asia. Screening for carriers of these traits is important to provide prenatal genetic counseling and to accurately estimate the true prevalence and public health burden of these disorders. The clinical course of thalassemias, which affect nearly 70,000 children annually, is highly variable depending on the mixture of inherited alleles. The primary forms of non-transfusion-dependent thalassemia include β-thalassemia intermedia, hemoglobin E β-thalassemia, and hemoglobin H disease. Early clinical recognition of these disorders is essential to prevent affected children from being mistakenly placed on life-long transfusion therapy.