The genes that everyone inherits contain coded information that influences which diseases any individual is most at risk of getting. Countless studies show that small variations in genes play a major role in a host of common maladies that produce untold suffering and premature death. However, progress in tying these variations to specific maladies has been slow.

On Oct. 26, the Broad Institute of Harvard and Massachusetts Institute of Technology announced publication of the largest catalog of common disease-related genetic changes ever assembled. It was prepared by an international group of 200 researchers from Canada, China, Japan, Nigeria, the United Kingdom, and the United States.

The catalog “is a powerful new tool for exploring the root causes of common diseases,” says David Altshuler, a member of the Broad Institute and associate professor of genetics at Harvard Medical School and Massachusetts General Hospital. “Such understanding is required for us to develop new and much needed approaches to prevent, diagnose, and treat many diseases.”

Previous studies show that any two unrelated people possess sets of about 25,000 genes that are 99.9 percent identical at the most basic level. In other words, your genes are roughly the same as those of Osama bin Laden, Martha Stewart, and Michael Jackson. Only 0.1 percent of the variable units in human genes account for all the inherited diversity in our looks, bodies, and behaviors.

But that 0.1 percent includes some 10 million small changes that make it more or less likely that any person will get one or more of the common diseases. They could explain why one person gets bipolar depression and others do not, why one medication successfully treats high blood pressure in one person but produces devastating side effects in another.