[Prenatal gene diagnosis of paternally inherited alpha-thalassemia by detecting fetal DNA in maternal plasma].

Objective: To evaluate the value of diagnosis of alpha-thalassemia by analyzing fetal DNA in maternal plasma.
Methods: Ten families were screened, the husbands being alpha-thalassemia Southeast Asia deletion (SEA alpha-thalassemia-1) heterozygotes and the pregnant women being alpha-thalassemia-2 heterozygotes. Fluorescent polymerase chain reaction (PCR) and gene scanning were used to detect the paternally inherited genotypes of SEA alpha-thalassemia-1 gene mutation and short tandem repeats (STRs) in the maternal plasma fetal DNA. The results were compared to those of conventional prenatal diagnosis of fetal DNA in amniotic fluid, chorionic villus or cord blood.
Results: Paternally derived STR genotypes were detected in all specimens of plasma fetal DNA. Paternally inherited SEA alpha-thalassemia-1 gene mutation was detected in 4 cases, while the other 6 cases did not inherit the paternal mutation. The results were completely concordant with those of the conventional prenatal diagnosis.
Conclusion: Noninvasive prenatal diagnostic method, the technique using fluorescent PCR and gene scanning to detect the fetal DNA and paternally inherited SEA alpha-thalassemia-1 gene mutation in maternal plasma helps exclude the fetuses with hemoglobin H diseases.