RESUMO
BACKGROUND AND AIMS: A pilot screening program for thalassemia was initiated in the Lao People's Democratic Republic. This study aimed to describe the genotype diversity and hematologic features of thalassemia among the participating pregnant women. METHODS: Blood samples of 411 pregnant Laotian women were collected. Hemoglobin (Hb) profiles were determined using a capillary zone electrophoresis system. Mutations of α- and ß-globin genes were investigated using a polymerase chain reaction and related techniques. RESULTS: As many as 26 different thalassemia genotypes including non-transfusion-dependent thalassemia, i.e. Hb E-ß-thalassemia, Hb H, and EA Bart's diseases, were identified. A variety of phenotypic expressions of hematologic features and Hb profiles were observed, including an unusual phenotype of Hb E-ß0 thalassemia with 89.1% Hb E, 1.6% Hb F, and 9.3% Hb A2. CONCLUSIONS: The remarkable genotype-phenotype diversity indicates a need for careful laboratory interpretation in order to provide appropriate genetic counseling and care to the Laotian population.
Assuntos
Povo Asiático/genética , Hemoglobinas Anormais/genética , Talassemia/genética , alfa-Globinas/genética , Globinas beta/genética , Adulto , Estudos Transversais , Eletroforese Capilar , Feminino , Estudos de Associação Genética , Genótipo , Hemoglobina E/genética , Humanos , Laos , Fenótipo , Gravidez , Talassemia/patologiaRESUMO
Screening for thalassemia carriers should not only be conducted in middle-income countries but also can be possible in low-middle income countries, through cooperation of experienced professionals from middle income countries. We describe a collaborating model between two close neighboring countries in establishing such a screening program for thalassemia. After training and setting up of facilities, a total of 152 out of 187 hospital staff were screened as a pilot activity to encourage community participation. Referring system for sending blood samples to a reference center in Thailand was also established. Among 152 health staff, 12.5% α0-thal, 2% ß-thal and 13% Hb E carriers were found. Applying thalassemia screening to 411 pregnant women and 71 spouses, 5 couples at risk of bearing a child of thalassemia disease were identified. The thalassemia screening program has a sensitivity of 99.5%, specificity of 77%, positive predictive value of 73%, and negative predictive value of 99.5%. Thus, it is possible to operate a thalassemia screening program with acceptable performance in a low-middle income country (Lao People's Democratic Republic) with the cooperation of a referral center located within close proximity in a middle income country (Thailand).
