Predicting childhood diabetes.

A child with antibodies against insulin-manufacturing cells, low levels of insulin production and who shares certain genes with a sibling who has insulin-dependent diabetes is likely to develop the disease, according to a study by Fredda Ginsberg-Fellner and colleagues that appears in the Sept. 20 JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION (JAMA).

The findings, made at the Mount Sinai School of Medicine in New York and the National Institutes of Health in Bethesda, Md., are similar to results published in the Aug. 22 NEW ENGLAND JOURNAL OF MEDICINE by researchers from the Joslin Diabetes Center in Boston. The Joslin study showed that even without checking for the genetic similarity, the antibody and insulin measurements can be used to predict subsequent diabetes.

The JAMA study followed, for an average of 4-1/2 years, 351 nondiabetic siblings in 178 families with one or more juvenile diabetics. Of the ten siblings who became diabetic, eight shared a specific set of genes linked to a diabetes, and months to years before clinical diabetes appeared all had lower-than-normal levels of insulin secretion as well as antibodies to insulin producing cells.

By alerting people at risk, it lessens the chances of the new diabetic going into diabetic shock before the disease is recognized, says Sri Srikanta, one of the Joslin researchers. More importantly, he says, studying the disease before clinical signs appear will help to identify the mechanism of diabetes and will also identify likely participants in experiments to identify factors that may prevent the disease.

The immediate clinical value of knowing who is at high risk of getting insulin-dependent diabetes is limited, Richard A. Guthrie of the Kansas Regional Diabetes Center in Wichita says, since there are no established preventies. "The great value is in research. We can learn more about the etiology and natural history of the disease."

These and other early diagnosis studies have already shown that the disease is not a sudden occurrence, as had been thought (SN: 2/19/83, p. 117). "The clock for the disease has been totally reset backwards," Srikanta says. "No one knew there was such a long latent period."