产前分子遗传诊断胎儿脆性X综合征的可行性分析

Feasibility Analysis of Prenatal Molecular Genetics in Diagnosis of Fetal Fragile X Syndrome

目的探讨产前分子遗传诊断胎儿脆性X综合征的可行性。方法回顾性分析我院行定期产前检查的49例具有家族性智能低下或潜在高危因素孕妇的临床资料,将其纳入A组;将同期行产前检查的150例健康志愿孕妇纳入B组。两组孕妇均于胎龄16～20周时行羊膜穿刺术取羊水标本检验,记录脆性X染色体的表达结果;进行为期2～3年随访,记录两组新生儿脆性X综合征发生情况,分析产前分子遗传诊断对预测新生儿脆性X综合征的特异度及敏感度。结果 1A组fra（X）阳性检出率为22.4%,显著高于B组的1.3%（P〈0.05）。2在为期2～3年的随访中,A组新生儿脆性X综合征及智力低下发生率分别为28.6%和46.9%,显著高于B组的0.7%和2.0%（P〈0.05）。3产前分子检测结果同随访结果对比,敏感度为78.6%（11/14）,特异度为99.3%（149/150）,漏诊率为6.1%（3/49）,误诊率为0.7%（1/150）。结论临床可将细胞遗传学检测作为辅助手段用于筛查具有家族性智能低下或潜在高危因素的孕妇,以提升脆性X综合征的产前检出率,达到优生优育的目的。

Objective To explore the feasibility of prenatal molecular genetics in diagnosis of fetal fragile X syndrome. Methods The clinical data of 49 pregnant women（group A） with familial mental retardation or potential high-risk factors admitted to our hospital for regular prenatal examination were retrospectively analyzed. At the same time, 150 cases of healthy pregnant women volunteers receiving prenatal examination were selected as group B. Both groups received amniocentesis to take amniotic fluid samples for testing at gestational age of 16 ~ 20 weeks. And the results of expression of fragile X chromosome were recorded; With a period of 2 to 3 years of follow-up, the incidence of neonatal fragile X syndrome was recorded and the specificity and sensitivity of prenatal genetic diagnosis in predicting neonatal fragile X syndrome were analyzed. Results 1The positive detected rate of fra（X） of group A was 22.4%, higher than 1.3% of group B（P〈0.05）. 2During the 2 to 3 years of follow-up, the occurrence rate of fetal fragile X syndrome and mental retardation were 28.6% and 46.9%of group A respectively, higher than 0.7% and 2.0% of group B（P〈0.05）. 3Comparing the results of prenatal molecular test with those of follow-up, the sensitivity was 78.6%, the specificity was 99.3%, the rate of missed diagnosis was 6.1%, and the rate of misdiagnosis was 0.7%.Conclusions Cytogenetic detection can be taken as a supplementary mean for screening of pregnant women with familial mental retardation or potential high-risk factors to improve the prenatal detection rate of fragile X syndrome and reach the purpose of eugenics.