Paterlini Bréchot P, Mouawia H, Saker A
Unité INSERM 807, faculté de médecine Necker-Enfants-Malades, 156 rue de Vaugirard, Paris, France.
Arch Pediatr. 2011 Jan;18(1):111-8. doi: 10.1016/j.arcped.2010.10.028. Epub 2010 Dec 21.
Cystic fibrosis (CF) is a frequently fatal autosomal recessive inherited disease affecting around one in 3000 newborns in France, the carrier frequency varying from one in 20 to one in 40 subjects depending on the geographical area. The disease is caused by a chloride channel defect that is attributable to mutations in the gene that encodes the CF transmembrane conductance regulator (CFTR). Approximately, 1200 different mutations have been discovered. Among them, the F508del mutation accounts for 70% of mutated alleles worldwide. Prenatal diagnosis (PND) of inherited monogenic disorders such as CF currently relies on invasive procedures--amniocentesis, chorionic villus sampling (CVS)--which carry a significant risk of miscarriage (from 0.5 to 3%). Several methods have been proposed to enrich circulating fetal cells (CFCs) from blood and use them in PND. However, up to now, no assay has been shown to be reliable enough for routine application in place of the invasive protocols. When combined with laser microdissection, isolation by size of epithelial tumor/trophoblastic cells (ISET) allows mutation analysis of DNA from single cells demonstrated to be fetal (circulating fetal trophoblastic cells [CFTC]) by short tandem repeat (STR) genotyping and uncontaminated with maternal DNA. Application of this protocol to 12 couples at risk of having a child affected by CF has shown, in a blind study, that the new method affords a reliable and safe PND of affected fetus, healthy carrier or normal non carrier fetus. A following prospective blind study has then been performed on 32 couples at risk of having an affected child. For each mother, five or 10 CFTCs have been analyzed with an individual genetic diagnosis performed per CFTC. Results have been obtained in 240 CFTC showing that seven mothers were carrying an affected foetus, with 100% sensitivity and 100% specificity. These results open the way to a multicenter clinical validation trial and to the potential future application of the ISET non invasive approach as a reliable alternative to the invasive PND procedures.
囊性纤维化（CF）是一种常导致死亡的常染色体隐性遗传病，在法国，每3000名新生儿中约有1人患病，根据地理区域不同，携带者频率在每20至40人中就有1人。该疾病由氯离子通道缺陷引起，这是由于编码囊性纤维化跨膜传导调节因子（CFTR）的基因突变所致。大约已发现1200种不同的突变。其中，F508del突变在全球突变等位基因中占70%。目前，诸如CF等遗传性单基因疾病的产前诊断（PND）依赖于侵入性操作——羊膜穿刺术、绒毛取样（CVS）——这些操作有流产的重大风险（0.5%至3%）。已经提出了几种方法来从血液中富集循环胎儿细胞（CFCs）并将其用于PND。然而，到目前为止，尚无检测方法被证明足够可靠，可常规应用以取代侵入性检测方案。当与激光显微切割相结合时，通过上皮肿瘤/滋养层细胞大小进行分离（ISET）可对经短串联重复序列（STR）基因分型证明为胎儿（循环胎儿滋养层细胞[CFTC]）且未被母体DNA污染的单细胞DNA进行突变分析。在一项盲法研究中，将该方案应用于12对有生育受CF影响孩子风险的夫妇，结果表明，这种新方法可为受影响胎儿、健康携带者或正常非携带者胎儿提供可靠且安全的PND。随后，对32对有生育患病孩子风险的夫妇进行了一项前瞻性盲法研究。对于每位母亲，分析了5个或10个CFTC，并对每个CFTC进行单独的基因诊断。对240个CFTC进行分析后得出结果，表明7位母亲怀有受影响的胎儿，敏感性和特异性均为100%。这些结果为多中心临床验证试验以及ISET非侵入性方法作为侵入性PND程序的可靠替代方法的潜在未来应用开辟了道路。
