Genomics solves mysterious disappearance of leprosy

No one wants to be labeled a leper. So powerful was the fear of leprosy in medieval Europe that its specter still exerts a hold on our collective psyche. Yet the disease itself is nearly unknown in developed countries today. To understand why the scourge of leprosy virtually disappeared, an international team of geneticists and archeologists systematically compared the genomes of five strains of Mycobacterium leprae, the bacterium responsible for leprosy, found in human remains buried in medieval graves. The findings, published in the 14 June 2013 issue of Science, indicate that the bacterium’s genome is nearly identical in the medieval and modern forms. For example, a medieval strain of M. leprae found in Sweden and the United Kingdom was nearly identical to the strain currently found in the Middle East. The research team suggests that host resistance may have been the result of social isolation and widespread infection rather than of bacterial mutation—people simply ceased becoming as susceptible to infection. The findings add to our understanding of the natural history of epidemics. In addition, the difficulty of isolating the bacterial DNA from human DNA fostered development of exquisitely sensitive sequencing methods that the authors report are among the most precise ever developed. The methods will assist isolation and sequencing of other difficult mixed and ancient DNA samples. In addition, the state of bacterial DNA preservation suggests that additional studies might be able to trace the path of leprosy even further back in time. —Karyn Hede, News Editor

Patently obvious

What has been self-evident to much of the genetics community for more than two decades has finally, at least in part, been affirmed by the highest court in the land. As most readers of this journal know, on 13 June 2013, the US Supreme Court ruled that Myriad Genetics’ patent claims covering the genomic versions of the BRCA1 and BRCA2 genes were invalid, on the grounds that genes are naturally occurring substances and that merely isolating them is insufficient to warrant patent protection. Although the court made clear that manipulated genes whose material properties have been changed (e.g., cDNA) may be patented, the overwhelming “take” on this decision is that it is a win for those who object to the patenting of human genes. Indeed, the impact of the decision was clear within hours of its announcement, when at least two large commercial laboratories announced plans to start offering sequence analysis of BRCA1 and BRCA2, either individually or as part of expanded panels.

It appears, then, that the long battle of those who have fought the patenting of human genes has largely been won, and the result will be expanded access and healthy competition among purveyors of genetic tests—a happy outcome for patients and those who care for them.

But the next battle looms. Properly interpreting the medical implications of genetic variants relies on access to data. However, Myriad Genetics has kept private the data obtained from their patent-protected analyses of countless women who have suffered from breast and ovarian cancer. The field (and patients) will suffer if such data remain sequestered for the perceived financial advantage of a single company. —James P. Evans, Editor-in-Chief

Genetics in Medicine | Mission Statement

Genetics in Medicine is a monthly journal committed to the timely publication of:

  • Original reports which enhance the knowledge and practice of medical genetics

  • Strategies and innovative approaches to the education of medical providers at all levels in the realm of genetics

As the official journal of the American College of Medical Genetics and Genomics (ACMG), the journal will:

  • Provide a forum for discussion, debate and innovation concerning the changing and expanding role of medical genetics within the broader context of medicine

  • Fulfill our responsibility to the College membership through the publication of guidelines, policy statements and other information that enhances the practice and understanding of medical genetics

Finally, as genetics becomes increasingly important in the wider medical arena, we will be an accessible and authoritative resource for the dissemination of medical genetic knowledge to providers outside of the genetics community through appropriate reviews, discussions, recommendations and guidelines.