This week, however Bryan Traynor, M.D. and John Hardy, Ph.D., scientist-grantees with the Packard Center for ALS Research at Johns Hopkins, are beginning the first in-depth screening for genes that underlie the "spontaneous" illness, which, like all ALS, destroys the motor neurons that enable movement, including breathing.
Hardy and Traynor are researchers in the National Institute on Aging's Laboratory of Neurogenetics in Bethesda, Maryland. Traynor also is a faculty member with the Johns Hopkins School of Medicine.
"In the forest of exciting research that's going on in ALS," says Packard Director, Jeffrey Rothstein, "this is a tall tree. We've been waiting some time for this one."
If all goes well, Traynor says, the work will clarify the role of genes - or lack of it - in sporadic ALS. "That role," he adds, "has long been uncertain. We don't know, for example, if sALS is triggered by a handful of interacting genes or genes plus environment or environment alone. The study aims to clarify that."
The results could strongly shape the search for a cure.
Supported by The Packard Center, the ALS Association and the National Institute for Neurological Disease and Stroke, the investigation stands out for several reasons: it's large enough for trustworthy results, involving close to 1,200 ALS patients and healthy controls. It brings in international scope: half of the study focuses on Italian populations. But most important, its razor-sharp technology - a high-throughput variety that uses robotics and just-available gene finder chips - mines each patient's DNA for information with a speed and accuracy not possible even a year ago. The research should be completed and data interpreted, the scientists say, early next year.
As a plus for ALS researchers worldwide, the raw DNA-based data from the study will quickly be made available online. Scientists expanding the study can add their data, improving accuracy of future research.
Why hasn't such a study gone on before? "Simply put, the technology wasn't available," Traynor explains. The research - known scientifically as a high-resolution genome-wide association study - relies upon spotting unusual patterns in patients' DNA (they're associated with having the disease) that healthy controls don't have or have far less frequently.
The patterns are sets of small variations in the order of the several billion bases that make up human DNA. Everyone has variations, known as single nucleotide polymorphisms, or SNPs (snips). Snips are useful because they can serve as signposts for the real quarry - disease-related genes. They're something like having a few different-colored beads on an otherwise-white necklace. If, say, the red bead always shows up in ALS patients, that's meaningful.
Fortunately, the Human Genome Project identified large numbers of SNPs. And last year, the completed HapMap project helped scientists pick out which are most revealing, i.e. those more likely to be near a gene-bearing stretch of DNA.
In the ALS study, the research team will search the genomes of 276 American sporadic ALS patients, testing them and a like number of controls for some 400,000 SNPs - a fair guarantee that no stretch of DNA will go unnoticed. As a check, the study includes DNA from 276 Italian patients and controls from a DNA bio-bank in Turin, Italy.
Under the logic that the signposts in patients' DNA associate physically near a sporadic ALS-related gene or genes, the study should make finding those genes far easier. "My gut feeling," Traynor says, "is that we'll find several tied to the disease."
"But even if get no associations, that's still a powerful result," he says. "That would suggest sporadic ALS isn't gene-based, that we should focus instead on the environment." If that's the case, the team is well situated. Not only is Italian collaborator Adriano Chio a noted investigator on environmental risk factors of ALS - he recently discovered that Italian soccer players had higher odds of having the illness - but the group also has an ongoing collaboration with a European consortium of ALS registries (EURALS), which actively surveys the populations of Italy, the UK and Ireland (25 million citizens) for ALS cases. To date, EURALS has collected health and lifestyle information on 900 patients and 1,700 controls.
Traynor, a genetic epidemiologist, is part of a project that's already combing registry data for risk factors.
This release was generated by The Packard Center for ALS Research at Johns Hopkins, an organization supported, in part, by the Johns Hopkins University School of Medicine.
About The Robert Packard Center for ALS Research at Johns Hopkins: www.alscenter.org
Located in Baltimore, the Robert Packard Center for ALS Research at Johns Hopkins is a worldwide collaboration of scientists aimed at developing therapies and a cure for amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease.
The Center is the only institution of its kind dedicated solely to the disease. Its research is meant to translate rapidly from the lab bench to the clinic, largely by eliminating time spent waiting for grants and lowering institutional barriers to sharing scientific results.
Scientists and clinician members of the Packard Center have moved drugs reliably and rapidly from preclinical experiments to human trials. Direct or indirect links to international biotech or pharmaceutical companies bring the infrastructure and experience needed to make promising drugs into therapies.
Packard scientists are the first to propose and test a combination approach to drug therapy, a tactic that has worked for AIDS, cancer and other diseases.
ALS is a progressive, disabling neuromuscular disease that causes complete paralysis and loss of function - including the ability to eat, speak and breathe. ALS progresses quickly and is not curable. Most patients die within five years of diagnosis.