page_title: Ariosa v. Sequenom
section_title: Background
hierarchical_section_title: Ariosa v. Sequenom / Background
caption_attribution_description: English: Amniocentesis. See a full animation of this medical topic.
context_page_description: Ariosa Diagnostics, Inc. v. Sequenom, Inc., 788 F.3d 1371, was a controversial decision of the Federal Circuit in which the court applied the Mayo v. Prometheus test to invalidate as patent-ineligible a patent said to "solve ... a very practical problem accessing fetal DNA without creating a major health risk for the unborn child." In December 2015, the Federal Circuit denied a motion for en banc rehearing, with several members of the court filing opinions urging Supreme Court review. On June 27, 2016, the Supreme Court of the United States denied Sequenom's petition for a writ of certiorari.
context_section_description: Sequenom is the exclusive licensee of U.S. Patent No. 6,258,540, which claims methods of using cell-free fetal DNA (cffDNA) circulating in maternal plasma (cell-free blood) to diagnose fetal abnormalities. Claim 1 is illustrative:
     1. A method for detecting a paternally inherited nucleic acid of fetal origin performed on a maternal serum or plasma sample from a pregnant female, which method comprises:
  amplifying a paternally inherited nucleic acid from the serum or plasma sample and
  detecting the presence of a paternally inherited nucleic acid of fetal origin in the sample.
  The point of the invention is that the inventors discovered in 1996 that fetal DNA might be floating around in the mother's blood (not just in the blood of the fetus, which was accessible only by invasive methods, such as amniocentesis, that created risks of miscarriage). Then they realized that they could selectively amplify the fetal DNA by focusing on the paternally inherited portion of its DNA (rather than the maternally inherited DNA).
  The claim itself has two simple and conventional steps: first amplifying (by polymerase chain reaction, PCR) and then detecting the paternally inherited DNA from the plasma sample. The technology for amplifying and detecting DNA was already well known and generally used to detect DNA. There was a problem, however, of how to ascertain which DNA in the sample was that of the fetus and which was the mother's (which greatly outnumbered the fetal DNA in the sample). 
  The inventors realized that the fetus had DNA derived from the father as well as the mother, and that paternal DNA was not native to the mother's blood. So they wanted to focus on genetic fragments containing paternally inherited sequences the mother did not share, but had traveled from the fetal blood into the maternal blood through the placenta. The paternal DNA in the mother's plasma had to have come from the fetus. Then, they could reliably identify fetal DNA, which would in turn allow them to diagnose certain fetal genetic conditions such as Down Syndrome, which can be detected by observing presence of extra chromosomes. The inventors now had a test that did not require amniocentesis, which is invasive and may cause miscarriages. Sequenom became the exclusive licensee of the patent. 
  After Sequenom launched its test on the market, several other companies began to market similar tests and cut prices. Sequenom sent letters to Ariosa Diagnostics, Inc., Natera, Inc. and Diagnostics Center, Inc.. threatening each of them with patent infringement suits. They responded by filing declaratory judgment actions against Sequenom.
  The district court construed the patent and denied a preliminary injunction, and Sequenom took an interlocutory appeal. On remand to the district court, it held the patent invalid as claiming the only viable method of detecting a natural phenomenon. The district court said: "[T]he claims at issue pose a substantial risk of preempting the natural phenomenon of paternally inherited cffDNA," which made them patent-ineligible. Sequenom then appealed to the Federal Circuit.
caption: Amniocentesis
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