Introduction: Beta thalassemia is a hereditary blood disorder characterized by anomalies in the synthesis of the beta chains of hemoglobin. Chorionic Villus Sampling (CVS) is used for fetal genotyping and as it is an invasive procedure, it has the risk of abortion. As a result, it is desirable to use a noninvasive method instead. The aim of this study was to present a noninvasive method for prenatal diagnosis of &beta-Thalassemia based on pattern of paternal polymorphism.

Materials & methods: In this study 30 families with the risk of thalassemia were screened. RFLP pattern of these families were identified and it was possible to investigate the transmission of paternal gene for thalassemia. Whole blood sample was drawn from mothers at gestation weeks 10-12 and their plasma was separated.

Findings: A cellular DNA of 7 plasma that contains DNA from both mother and fetus was investigated for RFLP informative sites of beta-globin gene.

Discussion & Conclusion: Although the amount of fetal DNA in plasma is less than maternal DNA, we could detect specific RFLP pattern of fetus and identified transmission of paternal allele.