Filipino β-thalassemia due to a large deletion: identification of the deletion end points and polymerase chain reaction (PCR)-based diagnosis

The gene frequency of β-thalassemia among Filipinos is estimated to be 0.02, although little is known about the mutations involved. Recently, an extensive β-thalassemia deletion was reported in several unrelated individuals of Filipino descent. The deletion begins approximately 4 kb upstream of the β-globin gene, and extends 3′ beyond the β-globin gene. In this report, we identify the 5′ and 3′ deletion endpoints and present a polymerase chain reaction (PCR) strategy for rapid DNA diagnosis of the Filipino β-thalassemia deletion.