January 2004 - Specific genetic markers may influence whether a person develops metabolic syndrome--a collection of health risks that increase the chance of developing heart disease, stroke and diabetes--according to new research published in December's Journal of Clinical Endocrinology and Metabolism (JCEM). A second study, which was published in the December issue of JCEM, also points to a link between Cushing's syndrome, a disease caused by overexposure to the hormone cortisol, and type 2 diabetes. The findings from the two new studies may help doctors identify patients who are at risk for developing complications related to obesity, diabetes and metabolic syndrome.
The Centers for Disease Control and Prevention estimates that metabolic syndrome affects 47 million Americans. Previous research has shown that the symptoms of metabolic syndrome are common among family members, yet a definitive genetic link has never been proven. In a new study, however, researchers at Pennington Biomedical Research Center in Baton Rouge, LA, demonstrate the existence of genetic regions that may signal a predisposition to metabolic syndrome.
Dr. Claude Bouchard and his colleagues analyzed 509 genetic markers to scan the whole genome of 456 white participants from 99 families and 217 black participants from 105 families who were part of the HERITAGE Family Study. All participants were between the ages of 17 and 65 years. The researchers specifically looked for genomic regions harboring genes that could influence metabolic syndrome. They found evidence of genetic linkages to metabolic syndrome in both black and white patients. Additionally, Dr. Bouchard and his team noted that the same chromosomal regions that they identified with metabolic syndrome have previously been linked with cardiovascular disease and type 2 diabetes risk factors.
"Our research shows a genetic link, contributing to the clustering in families and individuals, between diabetes, cardiovascular disease and metabolic syndrome. These findings bring us closer to discovering the actual genes that are responsible for metabolic syndrome, which puts patients at risk for so many serious health problems," explained Dr. Bouchard. "This information could someday help doctors assess whether specific patients are at risk for developing the metabolic syndrome based on their genes."
In a related study, doctors in France studied obese patients with type 2 diabetes to determine the prevalence of Cushing's syndrome (CS), which is a hormonal disorder caused when tissue is exposed to high levels of the hormone cortisol. Dr. Antoine Tabarin and his colleagues at the University Hospital of Bordeaux studied 200 overweight or obese patients with type 2 diabetes and poor metabolic control using a three-step diagnostic strategy that was designed to maximize the sensitivity of the screening process. Two percent of the subjects tested positive for CS. The diagnostic strategy involved the 1-mg overnight dexamethasone suppression test (DST), using a revised criterion for cortisol suppression, which maximized sensitivity to the procedure. This more sensitive test identified patients who would not have tested positive for CS using standard tests.
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"Our study demonstrated a relatively high prevalence of CS in obese diabetic patients. These findings hint that systematic screening for CS in obese patients may be worthwhile. In this perspective, our study indicates that more sensitive testing procedures may be necessary to accurately identify obese patients who are at risk for CS" explained Dr. Tabarin. "However, larger and longer studies are needed to confirm these findings. Additionally, we need to demonstrate that cure of these cases of subtle occult Cushing's syndrome has a beneficial impact on obesity and diabetes of patients."
Source: Endocrine Society