用高效液相色谱技术产前快速诊断β-地中海贫血

Usefulness of automated chromatography for rapid prenatal diagnosis of β-thalassemia in second trimester

目的 探讨应用高效液相色谱技术（HPLC）在孕中期快速产前诊断β-地中海贫血（β-地贫）的可行性。方法 夫妇双方均为β-地贫基因携带者的孕妇73例，在妊娠19—31W通过经母腹脐静脉穿刺的方法抽取胎血。胎血血红蛋白（Hb）各组分比例的测定采用HPLC，胎血β-地贫基因的检测采用PCR-反向点杂交的方法。结果 HPLC检出18例胎血只有HbF而无HbA，PCR—RDB证实此18例胎儿基因型均为β-地贫基因突变纯合子或双重杂合子。剩余55例胎血都有不等量的HbA，其中4例HbA值为0．5％～0．7％，均为带有-28基因突变的双重杂合子；51例HbA值范围1．4％～10．4％。其中30例为β-地贫基因突变杂合子，21例基因型正常。结论 对于重型β-地贫，用HPLC测定胎血HbA值和胎儿基因型分析进行产前诊断有很好的相符性。HPLC用在孕中期可以作为产前快速诊断重型β-地贫的-种方法。

To evaluate the usefulness of analysis of fetal blood in the mid - trimester of pregnancy by automated high performance liquid chromatography （ HPLC ） as a prenatal diagnisis method for β- thalassemia. Methods： Seventy - three pregnant women at risk of delivering a child with β- thalassemia major were identified using a hemoglobin electrephoresis test. Cordocentesis was performed at the gestational age of 19 -31 weeks and fetal blood was analyzed for hemoglobin fractions by HPLC. The β-globin gone mutations were characterized by PCR -reverse dot blot （RDB）. Results： HPLC revealed 18 fetuses whioh had only Hb F and no HbA. All were homozygotes or compound heterezygotes for β- thalassemia mutations. In the remaining 55 fetuses, a Hb A peak were present in the chrematograms. Four fetuses with 0. 5% - 0. 7% Hb A were compound heterezygotes for the - 28 mutations. Fiftyone fetuses had Hb A values ranging 1.4% ～ 10. 4%. Thirty of these were β- thalassemia heterezygotes, and 21 had normal β- globin genes. Conclusion： Complete agreement was showed between the results of Hb analysis by HPLC and direct genotyping by PCR - RDB. The diagnosis of β-thalassemia major in fetuses in the mid - trimester of pregnancy by HPLC analysis of Hb fractions is a suitsble alternative method for prenatal diagnosis.