Non-Invasive Prenatal Genetic Diagnosis – An Update

Today researchers employed by Sequenom published the results of a trial of their method of detecting fetal trisomy 21 (Down Syndrome) from the blood of pregnant women in the American Journal of Obstetrics. I have not yet been able to read the article, having been unwilling, thus far, to spend $30 to download it, but secondary sources report that the trial was a success.

The company looked at blood plasma from 480 women at higher than normal risk for having fetuses with trisomy 21. 31 of the samples were removed from the analysis for various technical reasons. Of the remaining 449 samples, the Sequenom test correctly identified all 39 cases of trisomy 21 (a sensitivity of 100%) and incorrectly identified only one of the 410 non-cases as positive (a specificity of 99.7%).

As discussed before in this blog, the method sequences the cell free DNA in the maternal serum and, basically, counts how many bits of chromosome 21 are present. This report, along with the January BMJ publication of the large trial by Dennis Lo’s group in Hong Kong, seems to me to make it all the more likely that non-invasive prenatal diagnosis of aneuploidies will be clinically available in the US soon . . . by 2012? But

will it be regulated by the FDA?
will it be paid for by insurers and Medicaid?
will it expand to Mendelian diseases and traits?
will (and should) we try to regulate the diseases and traits for which it is used?

We need to be exploring these questions!