Study Shows Type I Diabetes Is A Genetic Disease

A 40-year study of identical twins at the Barbara Davis Center for Childhood Diabetes is finding that four out of five people eventually develop the disease after their identical twin gets it first.

But the time lapse before the second twin gets it can be 10, 30 even 50 years.

 

“This study is telling us that Type I Diabetes is primarily a genetic disease,” said Dr. George Eisenbarth, who is the Executive Director of the Barbara Davis Center for Childhood Diabetes at the University of Colorado at Denver Medical School.

It’s also showcasing the roles several different genes play in diabetes and the steps a family member at risk can take to delay the onset.

“We know Type I diabetes develops because the body’s white blood cells attack and kill the cells that make insulin,” Eisenbarth said.

The 40-year study and a new one tracing 300,000 children at risk for the disease “tie into our being able to understand how to predict diabetes,” he said. “We now have tools to predict and trials to try to prevent Type I diabetes.”

Type I diabetes formerly was called Childhood Diabetes, but it can attack at any age and is characterized by the body’s inability to produce insulin.
By contrast, Type II diabetes usually is associated with lifestyle, such as obesity, that slows the body’s ability to keep blood sugar in balance.

Some 10 percent of the U.S. adult population has one form of the disease or the other.

Dr. Michael Savage’s identical twin developed Type I diabetes back in 1974, when they were both 27 years old. Identical twins have identical genes, so he was certainly susceptible.

Thirty years later, when he was 57, Savage developed the markers for diabetes. He now gives himself five shots a day to deliver insulin to his body. His body still is producing a bit of its own insulin, unlike his brother, who is completely dependent on injected insulin to keep his blood sugar in balance.

“Before diabetes develops, we can detect antibodies in the blood,” Eisenbarth said. Antibodies can precede the actual diabetes by 10 or 15 years — or maybe by just one year.

“We don’t know what the trigger is, after the genetic susceptibility. The first twin might get it at 12, and the second at 60,” Eisenbarth said.

About 2 in 5 Americans carry a gene that makes them at elevated risk for Type I diabetes. But the extreme risk comes when a person has inherited several genes from both mother and father, patterned in a way that make them particularly susceptible.
There has been a tremendous increase in Type I diabetes in Colorado and the nation — a doubling in just the past 25 years, Eisenbarth said.

“It probably has to do with the environment — something added or taken away over the last 70 years,” he said.

Aside from identical twins, if a sibling has diabetes, the other siblings have about a 1 in 20 chance of getting the disease.
Among people with no family history of the disease, the chances of contracting Type I are less than one in 300.

Some 40 genes are supposed to contribute to diabetes risk. Most of them are on chromosome 6.

The Barbara Davis Center is following 300,000 newborns who have at least one marker for diabetes risk, trying to determine if an environmental trigger causes certain of the children to develop the disease.

The kids enrolled in the study get periodic blood tests to see if their bodies are starting to develop the antibodies to fight diabetes — usually the first sign that the disease is on its way.

Researchers are working on a new approach in which medicines are infused just once a year to boost the number of regulatory T cells in people at risk for diabetes or autoimmune diseases, while slowing the manufacture of dangerous effector T cells.

“There’s a major worldwide effort now to find the set of genes that cause diabetes,” he said. “Some day, we hope to be able to screen for diabetes and autoimmune diseases, and develop therapy to prevent the illnesses.

“Human immunology is finally coming of age and attacking these common illnesses,” Eisenbarth said. The breakthroughs are a legacy of the Human Genome Project.

“We’re trying to delay the progress, but prevention is the goal.”

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FACT:
Blood sugar linked to normal cognitive aging: Maintaining blood sugar levels, even in the absence of disease, can be an important strategy for preserving cognitive health, suggests a study published by researchers at Columbia University Medical Center (CUMC).  Senior moments, or lapses in memory, according to this new research, could be blamed, at least in part, on rising blood glucose levels as we age. The findings suggest that exercising to improve blood sugar levels could be a way for some people to stave off the normal cognitive decline that comes with age.  The research shows that this is even true for people without diabetes since blood glucose levels tend to rise as we grow older.  See This Weeks’ Item #1

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