ABSTRACT
Objective To devolope a method for extracting DNA from dried blood spots (DBS)and optimizing the operating procedure,which could be applied to clinical gene diagnosis of thalassemia.And the cross contamination of DBS punching and the storage stability of DBS were studied.Methods A total of 1 50 blood specimens were collected,and DBS were prepared.Circles (3 mm in diameter)were punched in the DBS,and eluted with lysis buffer.The eluting method and operating procedure were opti-mized.Genomic DNA extracted from the elution solution by magnetic beads,and were performed thalassemia gene test.Finally jud-ging whether the results of DBS and whole blood were consistent.Two methods of thalassemia gene test were used in DBS and the compatibility of DBS processing method was verified.Judging whether there was cross contamination of DBS punching by the thalassemia gene test results of blank hole which were punched in the blank filter paper between thalassemia positive DBS.The DBS storage stability in thalassemia gene test was verified by detecting the DBS which were dry stored at room temperature for 6 and 9 months.Results 5 circles (3 mm in diameter)DBS were vibrating eluted at 55 ℃ for 1 hour,the DNA concentration extracted from the elution solution was 10-20 ng/μL,which was dissolved in 50 μL solution,and the DNA quality was good.The thalassemia gene test results of DBS and whole blood were the same,and the DBS results of two thalassemia gene test methods were the same too. The cross contamination of DBS punching was not detected in thalassemia gene test.The DBS which were dry stored at room tem-perature for 6 and 9 months could be stably performed thalassemia gene test.Conclusion DBS could be used to perform thalassemia gene test,which is accurate,convenient and stable.It is an ideal way for specimen referral of thalassemia gene test.
ABSTRACT
Objective To evaluate the value of prenatal gene diagnosis for thalassemia. Methods 128 fetuses suspected with thalassemia were performed amniocentesis or cordocentesis for gene diagnosis. Results No severe complications occurred during all procedures. 32 fetuses had normal genotype. 38 were heterozygous and 27 were homozygous of ?- thalassemia; 18 were heterozygous, 4 were homozygous and 9 were double heterozygous of ?-thalassemia. The types and frequencis of ?-thalassemia mutation were CD 41-42(47.5%), IVS-Ⅱ-654(42.5%), 17(A-T)(7.5%) and -28 (A-G)(2.5%) in turn. Pregnancies of 40 fetuses with severe thalassemia were terminated in time. Conclusions The screening and prenatal diagnosis of high risk fetus for thalassemia is safe, effective and accurate. It should be used as an obstetrical routine examination at the region with high thalassemia occurrence.