New Diabetes Marker

New Diabetes Marker

NEW MARKER FOR
DIABETES IDENTIFIED

Scientists at the National Institutes
of Health have identified a protein that is an important marker for type I (insulin
dependent) diabetes. The protein can be used in combination with two other known
marker proteins to improve diagnosis of individuals who have diabetes, and identify
those at risk of developing the disease. It and other marker proteins are candidates
for experimental treatments aimed at preventing the onset of type I diabetes.

The identification of the new marker protein, as

reported in the "Procedings of the National Academy of

Sciences", is part of an ongoing study at the National

Institute of Dental Research. Scientists at NIDR's

Laboratory of Oral Medicine are investigating the molecular

biology of diabetes, a condition which, on top of the risk

of heart, kidney, and eye complications, is known to

increase risk of gum disease and tooth loss.

IDDM, type I diabetes, is an autoimmune disease in

which the immune system produces antibodies that attack the

body's own insulin-manufacturing cells in the pancreas.

These antibodies, called autoantibodies, form the basis of

the existing diagnostic test for IDDM. In this test patient

serum reacts with sections of human pancreas tissue, a

labor-intensive procedure. Recently, however, scientists

have been able to identify some of the target proteins (that

react with the antibodies) in the pancreas, and are using

this knowledge to improve detection of diabetes and

streamline the screening process.

Doctors Michael Lan and Abner Notkins have now

identified two protein markers, IA-1, and IA-2, and cloned

and sequenced the genes for both. Genetically engineered

versions of both have been produced in the laboratory. The

two markers, when used in diagnostic tests, "recognized"

antibodies in 70% of IDDM patients. Combining them with a

third marker, a protein called GAD-65, increased the

recognition rate to 90% in persons with IDDM. Furthermore,

the presence of autoantibodies to the marker proteins in

otherwise normal individuals was highly predictive in

identifying those at risk of ultimately developing clinical

symptoms of the disease.

"The identification and production of these markers

makes it possible to develop a rapid and effective test to

screen large populations for IDDM," says Dr. Notkins. "In

addition, the proteins are candidates for immune tolerance

studies, which attempt to prevent the development of

destructive antibodies and subsequent disease."

Persons without diabetes also have the marker proteins

on their beta cells, but do not make antibodies. The

scientists are hopeful their research will aid in uncovering

the actual cause of type I diabetes.