γ Chain Abnormalities and γ-Globin Gene Rearrangements in Newborn Babies of Various Populations

Abstract

The present review provides a summary of quantitative hemoglobin data and lists the results of gene mapping and sequencing analyses for blood samples from newborn babies of different countries. Methodology suitable for such studies is reviewed, various abnormal fetal hemoglobins are discussed, the occurrence of Hb Bart's (γ4) and of the embryonic chain is evaluated, and the various types of γ-globin gene rearrangements (₋A_γ. A_{γ-; −}G_γ. G_γ-; γ-thalassemia; γ-globin gene triplications, quadruplications, and quintuplications) are compared. The several tables list the frequencies of the common A_γT variant and of the different γ gene rearrangements in various populations, while the results of quantitative analyses suggest that most anomalies are not associated with disease.