Winter 1996
The hunt for genes that cause diabetes
The hunt for genes that cause adult-onset, or Type II, diabetes has been narrowed by teams of researchers from the Health Science Center and the Southwest Foundation for Biomedical Research. Type II is the most common form of diabetes, affecting 15 million people in the United States alone.
Concentrating on four regions of human genetic material that may contain diabetes genes, the scientists are particularly interested in a region of human chromosome 11 and are scrutinizing another region of 11 and two regions of chromosome 6.
"We've found evidence implicating these regions. What it means is, we now know what haystacks the needles might be in," said Michael Stern, MD, professor of medicine and chief of the Health Science Center's division of clinical epidemiology. The "haystacks" in this case are human chromosomes and the "needles" are blocks of genes, perhaps 500 or so. Narrowing the search is a step forward, considering that the human genome (the term for a person's genetic blueprint) contains some 100,000 genes.
"Sifting through 500 genes is certainly better than sifting through 100,000," Dr. Stern noted.
The research is supported by grants from the National Institutes of Diabetes, Digestive and Kidney Diseases, a component of the National Institutes of Health. Study leaders are Dr. Stern, principal investigator; Peter O'Connell, PhD, co-principal investigator and professor of pathology at the Health Science Center; and John Blangero and Braxton Mitchell, both PhD associate scientists with the Southwest Foundation's department of genetics.
Scientists believe Type II diabetes is caused by a combination of genes and environmental factors rather than by a single gene. Learning which genes are involved in diabetes could someday lead to drug therapies involving those genes. Since the prevalance of Type II diabetes in the Mexican American population is roughly three times higher than in the general U.S. population, blood samples taken from 579 Mexican Americans in 30 South Texas families were studied.
