RESUMO
BACKGROUND: Non-invasive prenatal testing (NIPT) by massively parallel sequencing is a useful clinical test for the detection of common fetal aneuploidies. While the accuracy of aneuploidy detection can approach 100%, results discordant with the fetus are occasionally reported. In this study we investigated the basis of a discordant T21 positive and T18 negative NIPT result associated with a T18 fetus confirmed by karyotyping. METHODS: Massively parallel sequencing was used to detect fetal DNA in maternal circulating plasma. The parental origin and nature of the fetal and placental aneuploidies were investigated by quantitative fluorescent PCR of short tandem repeat (STR) sequences and by copy number variation (CNV) sequencing. RESULTS: There was no evidence of T21 maternal mosaicism, T21 microchimerism or a vanishing twin to explain the discordant NIPT result. However, examination of multiple placental biopsies showed both T21 and T18 mosaicism, including one confined region with a significantly higher proportion of T21 cells. Based on fetal DNA fractions and average mosaicism levels, the effective T21 and T18 fetal DNA fractions should have been sufficient for the detection of both trisomies. CONCLUSIONS: In this pregnancy, we speculate that confined placental region(s) with higher proportions of T21 cells were preferentially releasing fetal DNAs into the maternal circulation. This study highlights placental mosaicism as a significant risk factor for discordant NIPT results.
Assuntos
DNA/sangue , Feto/citologia , Placenta/citologia , Diagnóstico Pré-Natal , Trissomia/diagnóstico , Trissomia/genética , Cromossomos Humanos Par 18/genética , DNA/genética , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Gravidez , Análise de Sequência de DNA , Síndrome da Trissomía do Cromossomo 18 , Adulto JovemAssuntos
Ácido Fólico/metabolismo , Cardiopatias Congênitas/genética , Metilenotetra-Hidrofolato Desidrogenase (NADP)/genética , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Polimorfismo Genético , Pré-Escolar , Cistationina beta-Sintase/genética , Ácido Fólico/sangue , Predisposição Genética para Doença , Cardiopatias Congênitas/enzimologia , Humanos , Lactente , Recém-Nascido , Metiltransferases/genética , Antígenos de Histocompatibilidade Menor , Fatores de RiscoRESUMO
OBJECTIVE: To observe the killing effect of sodium abietate on adult male and female worms of Schistosoma japonicum in vitro. METHODS: The mice infected with cercariae of S. japonicum were sacrificed and perfused five weeks later, the adult worms obtained by the portal perfusion method, were cultivated in DMEM medium containing different concentrations of sodium abietate for 3 days, except the controls, then the worms were observed for the death and motility reducing. The worms were stained by hydrochloric acid carmine for the detection of the changes, and the protein of the worms was detected by using the ultraviolet ray-absorption and Bradford method. RESULT: After the treatment of sodium abietate, the mortality and motility reducing rate of adult worms were higher significantly than the controls; the effect of sodium abietate on male worms was more obvious than on female worms. The male worms' intestinal canal enlarged and appeared black or brown bands or spots after the treatment. The contents of the intestine of female worms were distributed asymmetrically, and the shape of some worms' ovaries was anomalism and the coloring was asymmetrical. Compared with the control group, the protein of adult male and female worms were reduced (P < 0.05). CONCLUSION: Sodium abietate could kill adult worms of S. japonicum in vitro. It may affect the protein metabolism of the worms.
