Task: Answer Verification
Input (English): Question: Are pLAC4 and beta-HCG mRNA levels altered in the maternal circulation of pregnancies with trisomy 21?
Answer: Maternal blood levels of beta-HCG-, PLAC4- and PAPP-A mRNAs are not useful markers for the screening of pregnancies with trisomy 21 as their concentrations are either not significantly altered (beta-HCG and PLAC4) or too low to be detected (PAPP-A).
Output (English): no