RESUMO
BACKGROUND: There is great need for the development of highly accurate cost effective technologies that could facilitate the widespread adoption of noninvasive prenatal testing (NIPT). METHODS: We developed an assay based on the targeted analysis of cell-free DNA for the detection of fetal aneuploidies of chromosomes 21, 18, and 13. This method enabled the capture and analysis of selected genomic regions of interest. An advanced fetal fraction estimation and aneuploidy determination algorithm was also developed. This assay allowed for accurate counting and assessment of chromosomal regions of interest. The analytical performance of the assay was evaluated in a blind study of 631 samples derived from pregnancies of at least 10 weeks of gestation that had also undergone invasive testing. RESULTS: Our blind study exhibited 100% diagnostic sensitivity and specificity and correctly classified 52/52 (95% CI, 93.2%-100%) cases of trisomy 21, 16/16 (95% CI, 79.4%-100%) cases of trisomy 18, 5/5 (95% CI, 47.8%-100%) cases of trisomy 13, and 538/538 (95% CI, 99.3%-100%) normal cases. The test also correctly identified fetal sex in all cases (95% CI, 99.4%-100%). One sample failed prespecified assay quality control criteria, and 19 samples were nonreportable because of low fetal fraction. CONCLUSIONS: The extent to which free fetal DNA testing can be applied as a universal screening tool for trisomy 21, 18, and 13 depends mainly on assay accuracy and cost. Cell-free DNA analysis of targeted genomic regions in maternal plasma enables accurate and cost-effective noninvasive fetal aneuploidy detection, which is critical for widespread adoption of NIPT.
Assuntos
Transtornos Cromossômicos/genética , DNA/genética , Síndrome de Down/genética , Feto/metabolismo , Diagnóstico Pré-Natal , Análise de Sequência de DNA , Análise para Determinação do Sexo/métodos , Trissomia/genética , Transtornos Cromossômicos/sangue , Cromossomos Humanos Par 13/genética , Cromossomos Humanos Par 18/genética , DNA/sangue , Síndrome de Down/sangue , Feminino , Humanos , Gravidez , Síndrome da Trissomia do Cromossomo 13 , Síndrome da Trissomía do Cromossomo 18RESUMO
OBJECTIVE: The aim of this study is to prevent false positive results in non-invasive foetal sex determination from pregnant women's plasma following strict anti-contamination criteria. METHODS: cffDNA from 200 pregnant women (mean gestational age of 8.3 ± 0.2 weeks) was analyzed based on genetic forensic anti-contamination procedures and classical non-invasive foetal sex determination techniques. RESULTS: No false positive or false negative was reported. The sensitivity and the specificity reached both a 100% value. CONCLUSIONS: Prevention of contamination following our anti-contamination criteria is a good practice for certain non-invasive sex determination, using cffDNA.