INTRODUCTION: Non-invasive prenatal diagnosis (NIPD) of Down syndrome is rapidly 
evolving. Currently, two applications for NIPD of Down syndrome have been 
developed with potential and have displayed positive results; the NIPD using 
next-generation sequencing technologies and the NIPD using the methylated DNA 
immunoprecipitation (MeDIP) real-time quantitative polymerase chain reaction 
(qPCR).
AREAS COVERED: The MeDIP real-time qPCR approach is based on the identification 
of differentially methylated regions (DMRs) and their use for discriminating 
normal from Down syndrome cases. DMRs were identified using high-resolution 
oligo-arrays. A subgroup of DMRs was selected for further investigation. Through 
the design of a discriminant equation which combines the results obtained from 
different DMRs, normal and abnormal cases are correctly classified indicating 
100% sensitivity and specificity.
EXPERT OPINION: Previous studies have also identified DMRs between non-pregnant 
female blood and placental DNA. However, these methods have been associated with 
a number of limitations including the low sensitivity and/or specificity of the 
assays, the limited number of identified DMRs or methylation sensitive sites and 
SNPs located on DMRs. These limitations have been overawed by the development of 
the MeDIP real-time qPCR-based methodology.