地中海贫血基因携带者产前筛查及实验室指标的评价

Prenatal screening for thalassemia gene carrier and appraisal for related laboratory indices

目的：调查本地区围产期妇女地中海贫血（简称“地贫”）基因携带率和基因突变类型，探讨多项实验室指标在产前地中海贫血基因携带者筛查中的临床应用价值。方法：对产前检查的孕妇，作地中海贫血基因分析、血常规红细胞参数检测、血红蛋白电泳HbA2定量以及铁代谢指标血清铁（SI）、血清铁蛋白（SF）测定。对已明确诊断的α地贫组84例、β地贫组85例以及缺铁性贫血（IDA）组76例，进行红细胞参数（RBC、Hb、HCT、MCV、MCH、MCHC、RDW、RET）以及铁代谢指标SF、SI结果的比较；并将各方法检测结果与地中海贫血基因诊断结果比较，分析各筛查方法的敏感性和特异性。结果：3750例孕妇共检出α地贫202例，基因携带率为5．4％；β地贫135例，基因携带率为3．6％。地贫组与IDA组比较，地贫组和IDA组Hb、HCT、MCV、MCH和MCHC均减低，RDW和RET均增高，与健康对照组比较，差异均有统计学意义（P〈0．01）。地贫组MCV减低较IDA组明显，两者之间差异有统计学意义（P〈0．05和P〈0．01）。IDA组SF降低而地贫组SF增高，两者之间差异有统计学意义（P〈0．01）。对照基因检测结果，MCV诊断地贫基因携带者的敏感性为97．6％，特异性为54．5％，若联合SF检测，特异性可达97．0％。HbA2定量对B地贫基因携带者的敏感性为96．8％，特异性为97．4％。结论：MCV结合SF检测可作为产前地贫携带者筛查的简便而有价值的指标。HbA2定量是β地贫携带者筛查可靠的血液学指标。基因诊断的优点是可确定基因突变类型，更可诊断α和β复合型地贫。

Objective The purpose of this study is to investigate the frequency and mutations of alpha-and beta-thalassemia for prenatal population of Shunde area, and to explore the applicable value of related laboratory indices in carrier screening of alpha-and beta-thalassemia. Methods Haematological routine, Hb electrophoresis for quantitating HbA2, thalassemia gene analysis, serum iron （SI） test and serum iron ferritin （SF） test were carried out for all subjects. Values of RBC, Hb, HCT, MCV, MCH, MCHC, RET, RDW, SI and SF were used for comparative study in iron deficiency anemia group （n=76）, mild alpha-thalassemia group （n=84） and mild beta-thalassemia group （n=85）. And the results were compared with gene analysis in order to evaluate sensitivity and specificity of the haematological indices. Results 202 cases （5. 4%） of alpha-thalassemia mutation and 135 cases （3.6%） of beta-thalassemia mutation were identified in 3 750 population. Compared with the normal group, RBC parameters including Hb, HCT, MCV, MCH and MCHC increased significantly in IDA group and thalassemia group, while the levels of RDW and RET were significantly elevated. The differences of the RBC parameters were significant as compared with those of control group （P 〈0.01）. MCV in alpha-and beta-thalassemia groups was significantly lower than that in IDA group （P〈 0.05 and〈0.01 respectively）. SF in IDA group was obviously lower than that in control group （P〈 0.01） but SF in thalassemia groups was obviously higher than that in control group （P〈0.01）. In ad- dition, compared with gene analysis, the sensitivity and specificity of MCV was 97.6 % and 54.5 % respectively in diagnosing thalassemia, and the specificity of combined test of MCV and SF accounted for97% in diagnosing thalassemia. The sensitivity and specificity for HbA2 quantitation was 96.8M and 82.9% respectively in diagnosing beta-thalassemia. Conclusion The combined test of MCV and SF may be used as a simple and effective laboratory means for prenatal screening of alpha- and beta-thalas- semia. HbA2 is a reliable hematological index in surveying carriers for beta-thalassemia. Gene analysis can identify gene mutation types and definitely-diagnosing combined type of alpha- and beta-thalassemia.