Epidemiology

Mutations in the beta-globin gene cluster occur at high frequencies (>1%) in regions including the Mediterranean, Middle East, northern Africa, India, and almost all of Southeast Asia.[3]

These mutations have arisen spontaneously, and it has been proposed that the carrier state for this disorder and others such as sickle cell disease may confer a survival advantage in areas where malaria is endemic.[4]Plasmodium falciparum parasitemia is reduced in vitro in beta-thalassemia.[5] The higher concentration of fetal hemoglobin (HbF) found in the red cells of people with hemoglobinopathies inhibits the development of the malarial parasite, but the mechanism of this effect is not well understood.[6][7]

Although the prevalence of these mutations is lower in the populations of northern Europe and North America, widespread immigration has led to worldwide distribution.[8] Approximately 1.5% of the global population are heterozygous (carriers) for beta-thalassemias.[9]

Compound heterozygosity of beta-thalassemia with hemoglobin E mutations may have a phenotype similar to beta-thalassemia major or intermedia. The gene frequency for the hemoglobin E mutation is high in Thailand, Laos, Cambodia, and parts of southern China.[10]

It is estimated that over 90% of children born with significant beta-thalassemia syndromes are from Asia, India, and the Middle East, and a large number involve hemoglobin E mutations.[11] In the developed world, newborn screening ensures early diagnosis and referral to the appropriate hematology service for management.

Use of this content is subject to our disclaimer