British scientists have found a weak link in our DNA that may be responsible for 95% of the 1.6 million cases of inflammatory bowel disease (IBD) plaguing Americans. In an exciting leap forward to curing these common and debilitating conditions, the research team also identified existing drugs that appear to reverse the disease in laboratory experiments, and human trials are in the works, says the BBC.

According to the Crohn's & Colitis Foundation of America, the number of people living with IBD is growing, with about 70,000 new cases diagnosed in the U.S. each year. There may be as many as 80,000 children in America suffering from IBD. The most common diseases that fall under the IBD umbrella include Crohn’s disease and ulcerative colitis, characterized by chronic inflammation in the gastrointestinal (GI) tract.

Inflammation impairs the ability of the GI organs to function properly, leading to symptoms of persistent diarrhea, abdominal pain, rectal bleeding, weight loss, and fatigue. Until now, there has been no cure for IBD, although scientists have recognized that genetics, the immune system, and environmental factors may all play a role in causing the disease.

The group of researchers from The Francis Crick Institute and University College London zeroed in on white blood cells, called macrophages, that play a key role in causing inflammation by releasing chemicals called cytokines in the intestines. They discovered the DNA code that regulates the inflammatory chemicals the macrophages release.

“This is undoubtedly one of the central pathways that goes wrong when people get inflammatory bowel disease,” said researcher Dr. James Lee, from The Francis Crick Institute. “It is the process by which one of the most important cells that causes inflammatory bowel disease goes wrong.”

The new study, published in the journal Nature, said that existing drugs could calm the excessive inflammation when the researchers experimented with them using samples from patients with IBD.

“We found not only how and why it goes wrong, but potentially a new way of treating these diseases,” said Lee, who is also a consultant gastroenterologist at the Royal Free Hospital. The new goal is to find a way to target the macrophages without causing side effects throughout the body, and clinical trials are expected to begin within five years.

“This research is a really exciting step towards the possibility of a world free from Crohn’s and colitis one day,” said Ruth Wakeman, from Crohn’s and Colitis U.K. “Crohn’s and colitis are complex, lifelong conditions for which there is no cure, but research like this is helping us to answer some of the big questions about what causes them.”