Myriad Genetics, Inc. is an American molecular diagnostic company based in Salt Lake City, Utah, United States. Myriad employs a number of proprietary technologies that permit doctors and patients to understand the genetic basis of human disease and the role that genes play in the onset, progression and treatment of disease. This information is used to guide the development of new molecular diagnostic products that assess an individual's risk for developing disease later in life (predictive medicine), identify a patient's likelihood of responding to a particular drug therapy (personalized medicine), assess a patient's risk of disease progression and disease recurrence (personalized medicine), and measure disease activity. Myriad's discovery of the breast cancer gene, BRCA1 was universally acclaimed as a monumental achievement: “There is no more exciting story in medical science.” Myriad was the subject of scrutiny after it became involved in a lawsuit over its patenting practices, which led to the landmark Supreme Court decision Association for Molecular Pathology v. Myriad Genetics, Inc..

In August 2016 Myriad announced it would acquire Assurex Health for up to $410 million, expanding the company's genetic testing for psychotropic medicine selection.

The global search for the genetic basis of breast and ovarian cancers began in earnest in 1988. In 1990, at an American Society of Human Genetics Meeting, a team of scientists led by Mary-Claire King, Ph.D., from the University of California, Berkeley announced the localization through linkage analysis of a gene associated with increased risk for breast cancer (BRCA1) to the long arm of chromosome 17. In August 1994, Mark Skolnick and researchers at Myriad, along with colleagues at the University of Utah, the U.S National Institutes of Health (NIH), and McGill University sequenced BRCA1. In 2013, the actress Angelina Jolie had her ovaries removed because she tested positive for a mutation in the BRCA1 gene. This led to a surge in demand by women for genetic testing.

The founders of Myriad are Peter Meldrum (past President and CEO of Agridyne and past CEO and President of Myriad Genetics, Inc.), Kevin Kimberlin (Chairman of Spencer Trask & Co.), Dr. Walter Gilbert (Founder of Biogen) and Mark Skolnick (Adjunct Professor in the Department of Medical Informatics at the University of Utah).

Subsidiaries of Myriad Genetics include Myriad Genetic Laboratories, Inc., Myriad RBM, Crescendo Bioscience, Sividon Diagnostics, and, most recently, Assurex Health.

Myriad Genetics's intention to patent human genes led to intense controversy. Though patenting genes has been an established practice since the beginning of genetic research, it was alleged that because genes occur naturally in every human, patenting them would constitute an obstacle to biomedical research worldwide. It did create obstacles for competing businesses in testing for the gene, but did not interfere with scientists’ ability to study the gene. It was one of the most widely studied genes with more than 10,000 papers.

Secondly, because the discovery of their relevance to breast cancer was funded by the public.

Third, because the company was selling its breast cancer diagnostic test for a price many described as "outrageous": $4000, the price of a whole genome sequencing (around 20,000 genes analyzed), when the test only looked at two genes.Some also stated that its price for the breast cancer diagnostic test was "outrageous" ranging from $2,500 to $4,000.

Myriad Genetics was a defendant in the case Association for Molecular Pathology v. Myriad Genetics (formerly Association For Molecular Pathology et al. v. United States Patent and Trademark Office). Lawyers at the ACLU served as counsel for the plaintiffs. In the suit, medical associations, doctors, and patients sued Myriad Genetics to challenge seven United States patents on genes related to breast cancer and ovarian cancer.

Two of the company's patents on the BRCA1 and BRCA2 genes were ruled invalid on March 29, 2010 by Judge Robert W. Sweet in the U.S. District Court for the Southern District of New York. On appeal, the Court of Appeals for the Federal Circuit reversed the trial court in an opinion dated July 29, 2011 and held that the genes were eligible for patents.

On December 7, 2011, the ACLU filed a petition for a writ of certiorari to the Supreme Court. On March 26, 2012, the Supreme Court vacated the Federal Circuit's judgment and remanded the case for further consideration in light of Mayo Collaborative Services v. Prometheus Laboratories, Inc., in which the Supreme Court had ruled, just six days earlier, that more restrictive rules were required to patent observations about natural phenomena.

On August 16, 2012, the Federal Circuit reaffirmed Myriad's right to patent the genes although they denied rights to patent comparisons of DNA sequences. On November 30, 2012, the Supreme Court agreed to hear a second challenge to the two gene patents held by Myriad. Oral argument took place on April 15, 2013. On June 13, 2013, in Association for Molecular Pathology v. Myriad Genetics (No. 12-398), the US Supreme Court unanimously ruled that "A naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated", invalidating Myriad's patents on the BRCA1 and BRCA2 genes. However, the Court also held that manipulation of a gene to create something not found in nature—such as a strand of synthetically-produced complementary DNA (cDNA)—could still be eligible for patent protection.

Myriad Genetics has also been involved in litigation in Australia over the patentability of DNA sequences. Regarding BRCA1, the company succeeded in the Federal Court, both at first instance and on appeal to the full court, but in October 2015 lost in a unanimous decision of the High Court, D'Arcy v Myriad Genetics Inc.

In Australia an invention is patentable if, to begin with, it is a "manner of manufacture". The plurality in the High Court formulated the key question as: "Whether the invention as claimed is for a product made, or a process producing an outcome as a result of human action" (para [28]). It held that the product in issue continued to consist basically of genetic information that occurs naturally, had not been altered as a result of human action, therefore had not been "manufactured" and consequently was not patentable. The plurality reflected that a broader conception of patentability could, both by creating virtual monopolies and by blurring the boundaries of what might come to be patented, produce a chilling effect on research and application, contrary to the purposes of patent protection.

The appellant had cited the recent US Supreme Court decision for comparison. The High Court was also aware that its decision could conflict with recent judicial decisions, as well as patents legislation, in other countries, and possibly with Australia's international obligations; however, it considered these to be issues for the legislature, as well as denying that its decision in this case was intended to set a precedent with regard to genetic patenting generally. In addition, the rest of the court did not dissent from Gordon J's concluding observation: "It is important to notice that the claims made in the patents in suit in the United States of America considered in Association for Molecular Pathology v Myriad Genetics Inc 186 L Ed 2d 124 (2013) were claims to the particular genetic sequences and therefore radically different from the disputed claims in this appeal" (note 232).