AB061. Screening of thalassemia in the Philippines

Background and objective: The thalassemias are autosomal recessive disorders which result in reduced production of one or more subunits of hemoglobin. They are a growing public health concern. Prognosis is improving, however, there is a lack of estimates of the affected population, resources for prevention, control and management in the country. In light of recent findings on the severity and genetics of this inherited disorder, the authors aimed to summarize information on the epidemiology, screening, diagnostic procedures such as high performance liquid chromatography and genetic analysis of thalassemias in the Philippines.

Methods: Patients referred by hematologists from different parts of the country from 2008 to 2014 were included in the study. Peripheral blood extracted from the subjects were hemolyzed and subjected to Variant^TM high performance liquid chromatography (HPLC) for detection of thalassemias and hemoglobinopathies. Genomic DNA extracted in 55 clinically diagnosed beta thalassemic patients subsequently underwent GAP PCR and direct sequencing. In an ongoing study, extracted genomic DNA from 20 alpha thalassemic patients was analyzed using alpha thalassemia strip assay and direct sequencing.

Results: HPLC results showed that majority of the patients were beta thalassemics (47%) followed by alpha-thalassemics (15%). HbE disease was also found in 1% of the population. Interestingly, thalassemia and hemoglobinopathy interactions such as beta thalassemia with HbE interaction (2.2%) and alpha-beta thalassemia (0.4%) have also been reported. Of the 55 clinically diagnosed beta thalassemics who underwent molecular analysis, 10 published beta globin gene defects were observed in 35 patients. The FIL deletion was found to be the most prevalent mutation among the alpha thalassemic patients.

Conclusions: Preliminary data on the thalassemias suggest that these disorders deserve priority in the country’s health agenda. The Philippines still faces many challenges in the provision of basic care for thalassemic patients. The prevention of severe alpha and beta thalassemia is dependent on the availability of molecular characterization, supported by genetic counselling and targeted public awareness programs. This will reduce the economic burden and comprehensive and effective management of this problem in our country will be better achieved.

Keywords: Alpha-thalassemia; beta-thalassemia; Philippines