First Identification of the 3.5 kb Deletion (NC_000011.10: g.5224302-5227791del3490bp) on the β-Globin Gene Cluster in a Chinese Family

β-Thalassemia (β-thal) is one of the most common autosomal recessive disorders worldwide. It is caused mainly by point mutations or, more rarely, deletions on the β-globin gene, leading to reduced (β⁺) or absent (β⁰) synthesis of the β chains of hemoglobin (Hb). Molecular characterization of β-thal is essential for the prevention of this disease in the population. In China, more than 46 different mutations have been found, while approximately five large deletional types of β-thal have been reported. Here we described a large deletional mutation of the β-globin gene cluster previously unreported in the Chinese population, the 3.5 kb deletion (NC_000011.10: g.5224302-5227791del3490bp) removing the β-globin gene promoter and the whole β-globin gene leading to a β⁰-thal phenotype.