Prevalence and molecular characterization of beta-thalassemia in Filipinos

beta-Thalassemia (thal) is a common single-gene disease worldwide. However, the prevalence of beta-thal and the spectrum of beta-globin gene mutations in Filipinos remain unclear. This study sought to answer these two questio ns. A total of 2954 apparently healthy Filipinos in Taiwan were recruited f or a prevalence study. A complete blood count was done in every subject. Th ose with microcytosis were studied with hemoglobin (Hb) high-performance li quid chromatography to determine the levels of Hb A(2) and Hb F. Twenty-sev en subjects had elevated levels of Hb A(2) (>4.0%). These 27 suspected beta -thal carriers and another 16 beta-thal major patients who were being treat ed in the Philippines were studied to determine the spectrum of beta-globin gene mutations. Gap-PCR was used to detect the Filipino deletion of beta-t hal, and direct sequencing was used to detect point or small mutations in t he beta-globin gene. All of the 27 suspected beta-thal carriers had one mut ation in the P-globin gene, resulting in an overall prevalence of 0.9%. The spectrum of beta-thal mutations was similar in the carrier and patient gro ups Analysis of the pooled identified seven different mutations in the stud y population. The Filipino deletion was the most common mutation, accountin g for 45.8% (27/ 59) of the alleles, followed by codon 67 (-TG) (16 alleles ), and Hb E (11 alleles), These three mutations accounted for 92% of the Fi lipino beta-thal alleles, Elucidation of the beta-thal mutations in Filipin os is useful for the genetic counseling and prenatal diagnosis of this dise ase.