Non-invasive detection of fetal trisomy 21 using fetal epigenetic biomarkers with a high CpG density.

Lim, Ji Hyae; Lee, Da Eun; Kim, Kyeong Sun; Kim, Hyun Jin; Lee, Bom Yi; Park, So Yeon; Ahn, Hyun Kyong; Lee, Si Won; Kim, Moon Young; Ryu, Hyun Mee

Background: Non-invasive prenatal test of trisomy 21 (T21) is being researched using fetal specific epigenetic biomarkers present in maternal plasma. We applied a methyl-CpG binding domain-based protein (MBD) method based on epigenetic characteristics of fetal specific-methylated regions with a high CpG density in HLCS on chromosome 21 and RASSF1A on chromosome 3 for the non-invasive detection of fetal T21 and estimated the diagnostic accuracy of the method. Methods: A nested case-control study was conducted with maternal plasma collected from 50 pregnant women carrying 40 normal and 10 T21 fetuses. A MBD method was used for enrichment of methylated DNA regions in maternal plasma. The levels of methylated HLCS (M- HLCS) and methylated RASSF1A (M- RASSF1A) were simultaneously measured by multiplex qPCR. Results: Levels of M- HLCS and M- RASSF1A were obtained in all cases. Levels were not different according to fetal gender (p>0.05 in both). The level of M- HLCS was significantly increased in women with a T21 fetus compared with controls (p<0.001). The level of M- RASSF1A was not different between two groups (p>0.05). In non-invasive fetal T21 detection, the specificity of M- HLCS level and the epigenetic-epigenetic ratio (EER) using M- HLCS and M- RASSF1A levels were 82.5% and 92.5%, respectively, at 90.0% sensitivity. Conclusions: Our findings suggest that the EER may be useful as a potential biomarker for the non-invasive detection of fetal T21, regardless of fetal gender. The MBD method can be used as an effective tool in the detection of methylated fetal specific markers with a high CpG density in maternal plasma.

PRENATAL diagnosis; DOWN syndrome; BIOMARKERS; EPIGENETICS; CLINICAL chemistry

Clinical Chemistry & Laboratory Medicine, 2014, Vol 52, Issue 5, p641

1434-6621

Academic Journal

10.1515/cclm-2013-0802