【摘要】 目的对498例地中海贫血产前基因诊断结果和方法进行回顾性分析。方法对498例地贫产前诊断样本,包括羊水样本445例、绒毛样本50例和脐血样本3例,提取基因组DNA。缺失型α地贫的产前诊断采用跨越断裂点PCR(Gap polymerase chain reaction,Gap-PCR)技术和多重连接依赖式探针扩增(multiplex ligation-dependent probe amplificatio,MLPA)技术同时进行检测;非缺失型α地贫的产前诊断采用反向斑点杂交(reverse dot blot,RDB)技术进行检测。β地贫的产前诊断采用RDB技术和多色探针熔解曲线技术(multicolor melting curve analysis,MMCA)同时进行检测。对RDB方法检测不出的IVS-Ⅰ-1(G→T)纯合突变,改用DNA测序和MMCA的方法同时检测。对少见的缺失型β地贫采用MLPA方法进行检测。婴儿出生后半年电话随访婴儿表型。结果 498例产前诊断样本孕妇来自包括河北在内的17个省市,其中中重型α地贫高风险胎儿样本295例,中重型β地贫高风险胎儿样本134例,其他情况69例。α地贫基因检测共446例,其中产前诊断严重类型地贫87例(19.51%),包括巴氏水肿胎66例(14.80%)和Hb H病21例(4.71%),轻型186例(41.7%),正常胎儿173例(38.79%);β地贫基因检测共389例,其中严重类型地贫31例(7.97%),轻型98例(25.19%),正常胎儿260例(66.84%)。经DNA测序和MMCA检测到1例胎儿为IVS-Ⅰ-1(G→T)纯合突变。MLPA检测到1例胎儿父亲为β地贫东南亚型缺失(HPFH of SEA type),胎儿未检测到此缺失。1例样本结果为轻型α地贫同时合并18三体。87例严重类型α地贫胎儿、31例严重类型β地贫胎儿和1例轻型α地贫伴18三体胎儿均在围产期前后接受了终止妊娠的处理。结论地贫的人群分布已逐渐从南方地区向北方地区扩展。对中重型地贫高风险孕妇进行产前基因诊断,检出严重类型地贫胎儿,是降低高危地域严重类型地贫患儿出生的有效手段。对于RDB方法检测不出的纯合突变类型,可改用DNA测序和MMCA的方法进行检测;同时,对于β地贫的少见缺失类型应进行进一步检测,防止漏诊。另外,在进行地贫基因产前诊断的同时,要注意排除胎儿是否患有染色体病。更多还原

【Abstract】 Objective:The results and methods of prenatal diagnosis in 498 cases of thalassemia were analyzed retrospectively. Methods:The genomic DNA was extracted from 498 cases,including 445 amniotic fluid samples,50 fetal villi samples and 3 umbilical cord blood samples. The deletions of α thalassemia were detected by Gap-PCR and MLPA simultaneously while the mutations of α thalassemia were detected by RDB.RDB and MMCA were used simultaneously for β thalassemia.DNA sequencing and MMCA were performed when the homozygous mutation of IVS-Ⅰ-1(G→T)was not detected by RDB. The rare deletion types of β thalassemia were detected by MLPA.Follow-up visit were done half a year after the fetuses were born. Results:498cases of prenatal diagnosis came from 17 provinces,including Hebei province,of which 295 cases in the high risk of α thalassemia major,134 cases in the high risk of β thalassemia major and 69 cases of others. Alpha thalassemia was detected in 446 cases,of which the majors(n=87,19.51%),including Bart′s hydrops syndrome(n=66,14.8%)and Hb H disease(n=21,4.71%),the light type(n=186,41.7%)and the normal(n=173,38.79%).Beta thalassemia was detected in 389 cases,including the majors(n=31,7.97%),the light type(n=98,25.19%)and the normal(n=260,66.84%).One fetus was detected of the homozygous mutation of IVS-Ⅰ-1(G→T)by DNA sequencing and MMCA.One fetus′s father was detected of the Southeast Asian type(of SEA type HPFH)of β thalassemia by MLPA,while the fetus did not detect this deletion. Among the α thalassemia heterozygotes,there was one 18-trisomy.Follow-up visit found that babies with Bart′s hydrops syndrome(n=66),Hb H disease(n=21),β thalassemia majors(n=31)and α thalassemia heterozygote combined with 18 trisomy(n=1)were aborted. Conclusion:The population distribution of thalassemia has gradually extended from south to north.Prenatal diagnosis of thalassemia is the effective means of reduce the birth of thalassemia majors in the high risk region.DNA sequencing and MMCA should be used when the homozygous mutation was not detected by RDB,while the rare deletions of beta thalassemia should be further detected to prevent misdiagnosis.In addition,we should pay attention to whether the fetus have the chromosomal diseases when we have prenatal diagnosis for thalassemia.更多还原