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Telltale DNA aids early diabetes diagnosis

Medicine@Yale, 2011 - Nov Dec

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In type 1 diabetes, the immune system kills insulin-producing beta cells in the pancreas. By the time the illness is diagnosed, most beta cells have been destroyed, creating a challenge for potential treatments to be effective.

When cells die they rupture, and the DNA in their nuclei escapes into the bloodstream. Though the DNA sequence in every cell is identical, the body’s organs have diverse functions, so DNA is “marked” with tissue-specific modifications that enable or suppress the expression of appropriate genes.

In an early edition of Proceedings of the National Academy of Sciences, a group led by Kevan C. Herold, M.D., professor of immunobiology and medicine, describe a marker found only in beta-cell DNA. In a mouse model of type 1 diabetes, the team saw a rise in blood-borne beta-cell DNA just as the cells began to die, long before diabetes symptoms appeared. Higher levels of beta-cell DNA were also seen in newly diagnosed type 1 diabetes patients.

“Early detection of cell death may allow for better monitoring and earlier interventions in people at risk for developing type 1 diabetes,” says Herold.