Fifty years after participating in studies of pentosuria, an inherited disorder once mistaken for diabetes, 15 families again welcomed medical geneticists into their lives. Their willingness to have their DNA analyzed with advanced genomics technologies has solved a mystery more than a hundred years old.
Researchers from the University of Washington, Israel, and Switzerland reported the solution in the Oct. 31 Early Edition of the Proceedings of the National Academy of Sciences.
Their findings may help elucidate historical and geographical patterns of genetic mutations -- when and how human mutations appear and are carried over generations and with migration of human populations.
Pentosuria occurs almost exclusively in Ashkenazi Jews, whose ancestors trace back to the Middle Ages in Central or Eastern Europe. Traditionally, Ashkenazi Jews have married within their religious and ethnic group.
Dr. Arno Motulsky, professor emeritus of medicine, Division of Medical Genetics, and of genome sciences at the UW, and one of the founders of the discipline of medical genetics, was the senior author of the study. He was among the geneticist sleuths who tracked down the families and the genetic mutations responsible for the metabolic condition that ran in their families.
In the early and mid 20th century, clinical testing methods did not distinguish between pentosuria and diabetes mellitus. The confusion resulted in potentially dangerous treatment errors.
Diabetic patients have problems with increased levels of glucose, a six-carbon sugar, whereas pentosuria causes high levels of a five-carbon sugar, xylulose, in urine and blood. Pentosuria itself is completely harmless. But when pentosuria patients were misdiagnosed with diabetes and received insulin, their blood glucose levels plummeted and they suffered insulin reactions.
The diagnostic errors motivated New York City biochemist Margaret Lasker
|Contact: Leila Gray|
University of Washington