Increased Colon Cancer Risk Traced to Couple Who Sailed to America in 1600's

A couple who sailed to America from England around 1630 took with them a gene that has put their thousands of descendants at an increased risk of colon cancer.

An American team traced back a mutation found in two large families living in Utah and New York to a couple who were among the early settlers of America.

The team, from the Huntsman Cancer Institute in Utah, did not name the families but said thousands of people across the country may have the mutation that spread widely as the couple’s descendants branched apart over many generations.

“The fact that this mutation can be traced so far back in time suggests it could be carried by many more families in the United States than is currently known,” said Deb Neklason, who led the study. “In fact, this founder mutation might be related to many colon cancer cases in the United States.”

The study did not investigate whether the same mutation may also be responsible for colon cancers in the U.K., but that appears possible.

Less than 1 percent of cases in the U.S. are due to this particular genetic mutation, according to the study published in Clinical Gastroenterology and Hepatology.

The team first focused on the Utah branch of the family, which numbers about 5,000 people, 14 years ago because its members had an unusually high risk of colon cancer.

The Mormon faith of the family meant the researchers were able to mine a wealth of genealogical information taken from detailed church records over the years that is now part of a large genetics database in Utah, Neklason said.

While most of the records in the study related to the Utah part of the family, the researchers eventually identified the New York branch as well.

“We just know about these two branches of the family,” Neklason said. “The significance of it going so far back is there are probably many branches of the family out there that aren’t aware of the mutation.”

In the study, the team identified the mutation that causes a condition called attenuated familial adenomatous polyposis (AFAP), which makes people more prone to developing the polyps that can cause colon cancer.

Without proper treatment, people with this mutation have a greater than 2 in 3 risk of developing colon cancer by age 80, compared to about 1 in 24 for the general population. Early treatment, however, can just about eliminate this risk.

“This study highlights that you need to pay attention to your family history,” Neklason said.“With intervention to remove the polyps, the risk goes to near nothing.”